A microchip scan only ever returns a number. That number points to the registry that enrolled it, and the registry holds the contact record the number unlocks. While that record carries the previous owner's phone number, every call about your cat goes to a stranger's phone, no matter how long she has lived with you or how firmly she is yours in every other sense. Vets, wardens and finders cannot edit the record from their end, and your vet noting your number on her clinical file, while worth doing as a backup, does not change what a scan elsewhere will produce. The transfer has to happen at the registry itself, so that is where to put your energy.
Gather Your Proof Before You Call
Registries move a record from one keeper to another on evidence, so arrive with yours assembled. Your adoption papers or purchase receipt name you as her new keeper, vet records in your name show her in your ongoing care, and the chip number itself, which your vet can read with a quick scan, identifies the exact record to amend. The paperwork from her adoption or her previous practice usually names the registry holding the record; if it does not, the number's allocation tells the vet or the registry helpline which database it belongs to. If you are still in touch with the previous keeper, ask them to be available to confirm the handover, because their agreement is the fastest evidence a registry can be given. Do not be put off if the first person you speak to sounds doubtful; ask them to set out exactly which documents their process accepts, and supply those rather than arguing the case in general terms.
Work the Transfer Through
Contact the registry and ask plainly for a transfer of keepership, then follow the route they set. When the previous keeper confirms the change, transfers are usually straightforward and quick. When they cannot be reached, registries work through an evidence-based process instead, weighing your documents and often applying a waiting period during which the old keeper can object, so an unreachable previous owner slows the transfer rather than stopping it. Ask what the registry needs from you, what it will cost if anything, and how long each stage takes, and keep a note of every call and submission. Until the transfer completes, ask your vet to flag your number prominently on her clinical file, keep her indoors or supervised outside if you can, and treat any escape as especially urgent, because the usual safety net has a hole in it.
Confirm It, Then Keep It Current
Being told a transfer has been submitted is not the same as it being done. Confirmation means reading the saved record back, through the registry's own system, and seeing your name, your phone number and your address attached to her number, digit by digit. Only that read-back proves she became reachable the day the record changed. From then on, the record is maintained with the registry itself: if your number or address changes, update it there, and re-check it after any house move. Repeating that read-back after every change of phone number keeps the proof fresh. Updating any other profile does not touch the registry record, which is why the two layers must never be confused. Separately from the registry record, Verified QR ID Pet Profiles gives her a scannable page of your own in KinsLe, where a finder sees the details you have saved and can act on them straight away.