What you can and cannot change without the previous owner

You can change the contact information on a microchip registration without the previous owner's permission, but the process depends on which registry holds the chip and what information you have. Most registries allow you to update the phone number, address, and email linked to the chip if you can prove current ownership of the animal — usually by showing a vet record, adoption papers, or a recent purchase receipt with your name on it.

What you cannot do is change the actual microchip number itself or remove the previous owner's name from the registry without their involvement or a court order. The microchip number is permanent and tied to the animal's identity. If the previous owner's contact details are still listed as primary, a vet or shelter scanning the chip will reach them first, which can create problems if they no longer own the animal or are unreachable.

The fastest solution is to contact the registry directly — not the vet or shelter — and ask what documents they need to transfer ownership into your name. Different registries have different rules, so the answer depends on which one holds your chip's registration.

Key Takeaways

  • You can update contact information on a microchip registration by providing proof of current ownership, such as adoption papers or a vet record in your name.
  • The microchip number itself cannot be changed, and the previous owner's name may remain on the registry unless you follow the registry's transfer process.
  • Contact the registry directly — not your vet — to find out what documents they need to transfer ownership into your name.
  • If you cannot locate the previous owner, some registries allow you to file a change-of-ownership form or provide a statutory declaration to update the registration.
  • A vet or shelter will always scan the chip first, so updating the registration ensures they reach you, not the previous owner.

How to find which registry holds your microchip

Before you can change anything, you need to know which registry your chip is registered with. The microchip itself has a number printed on it, but that number alone does not tell you the registry. Your vet can scan the chip and tell you the number, and some scanners will also display the registry name — but not always.

The most reliable way is to contact the three largest registries in North America and give them the microchip number. HomeAgain, AKC Reunite, and Petlink each maintain their own databases. You can call or visit their websites, enter the chip number, and they will tell you whether it is registered with them. Once you find the right registry, you can ask them directly what you need to do to update the registration into your name.

If the chip is registered with a smaller or regional registry, your vet may be able to help you track it down. Keep the microchip number handy — you will need it for every conversation with the registry.

What documents the registry will ask for

Most registries ask for one of the following to prove you now own the animal: an adoption certificate with your name, a purchase receipt or bill of sale, a vet record dated after you took ownership with your name and address, or a shelter release form. Some registries also accept a statutory declaration — a sworn statement you sign in front of a notary or witness — if you adopted the animal informally or cannot locate the previous owner.

Have the microchip number ready when you contact the registry, and ask them to send you a list of what they accept before you gather documents. Different registries have slightly different rules, and some may ask for additional information like proof of your address or a photo ID. Getting the list upfront saves you a trip back and forth.

If you adopted the animal from a shelter or rescue, call them and ask for an adoption certificate or release form with your name on it. If you bought the animal from a breeder or private seller, a receipt or bill of sale works. If you have neither, a vet record is usually your strongest option.

Changing contact information when you have the documents

Once you have gathered your proof of ownership, contact the registry by phone or through their website. Most registries have an online form you can fill out, but calling is faster because you can ask questions and confirm what they need before you submit anything. Have your proof of ownership ready to photograph or scan — they will ask you to send it.

The registry will update your name, phone number, address, and email into their system. This usually takes a few business days. Once it is done, any vet or shelter that scans the chip will see your contact information first. Ask the registry to send you a confirmation email with the updated details so you have proof the change went through.

If the previous owner's name is still listed on the registration after you have updated your information, contact the registry again and ask them to remove it or mark it as inactive. Some registries do this automatically when you transfer ownership; others require a separate request.

What to do if you cannot locate the previous owner

If you adopted the animal as a stray, inherited it, or bought it from someone you no longer have contact with, you may not be able to reach the previous owner. Most registries understand this situation and have a process for it. Contact the registry and explain that you are now the owner but cannot locate the previous owner to request their permission to update the registration.

Many registries will ask you to provide a statutory declaration — a signed, notarized statement that you are the current owner and have made reasonable efforts to contact the previous owner. Some registries also accept a letter from a vet confirming that you have been the animal's primary caregiver for a certain period, usually at least six months. A few registries will update the registration based solely on your proof of current ownership, without requiring the previous owner's involvement.

If the registry refuses to update the registration without the previous owner's consent, ask whether they have a dispute resolution process or whether you can file a formal request with supporting documents. In rare cases, you may need to consult a lawyer, but most registries resolve these situations without legal action.

Why updating the registration matters

A microchip is only useful if the contact information is current. If a vet or shelter scans your animal's chip and reaches the previous owner instead of you, they may not be able to return the animal to you quickly — or at all, if the previous owner no longer wants to be involved. Updating the registration ensures that you are the first person contacted.

Outdated registrations also create confusion if the animal is lost or injured. A vet may spend time trying to reach an old phone number or address while your animal is waiting for care. Taking the time to update the registration protects your animal and makes sure you are notified if something happens.

Some registries also offer additional services like lost-pet alerts or recovery networks, but these only work if your contact information is correct. Once you have updated the registration, check whether the registry offers these services and sign up if they are available in your area.

Frequently Asked Questions

Can I change the microchip number if the previous owner's name is still on it?

No. The microchip number is permanent and cannot be changed. It is the animal's unique identifier. What you can change is the contact information and ownership details linked to that number. If the previous owner's name is still listed, contact the registry and ask them to remove it or transfer ownership into your name.

What if the registry says I need the previous owner's permission?

Ask the registry whether they accept a statutory declaration or a letter from your vet as an alternative. If they still refuse, explain that you cannot locate the previous owner and ask what their dispute resolution process is. Most registries have a way to handle this situation without requiring the previous owner's involvement, but you may need to provide additional documentation.

How long does it take to update a microchip registration?

Most registries update the information within a few business days of receiving your proof of ownership. Some do it the same day if you call and provide the documents over the phone. Ask the registry for a timeline when you contact them, and request a confirmation email once the change is complete.

Do I need to tell my vet that I updated the microchip registration?

You do not have to, but it is a good idea. Your vet has a record of the animal's microchip number, and updating your vet's records ensures that if they scan the chip, they know to contact you. It also helps if your vet needs to contact the registry on your behalf in the future.

What if the animal has multiple microchips?

Some animals have more than one microchip, especially if they were scanned at a shelter or vet and a new chip was implanted. Contact each registry separately and update the registration for each chip number. Ask your vet to scan the animal and confirm how many chips are present and which registries they are registered with.