Few admin changes carry as much quiet risk as a new phone number. Your cat's chip does not ring you; it yields a number, and someone with a scanner looks up the registry entry behind that number and dials whatever the entry shows. If that field still holds your old line, the call goes to a stranger, a disconnected tone, or a recycled number answered by someone who has never heard of her. The fix is a single field, but it has to be made in the right place and then chased through every copy.
The Registry Entry Comes First
Your registration record should hold the chip number, the registry's name, and your name, address, phone and email exactly as the registry holds them, plus a second contact person. The phone in that set is the field that changed, so amend it with the holding registry itself, not merely in your own notes or apps. While you are in the entry, scan the remaining fields for older drift, because a number change often travels with a move or a new email account. Then read the saved record back with the registry and confirm the new number sits there digit for digit, formatted as a caller would dial it. Submitted is not the same as stored, and this check is the difference.
Do the registry change from the new phone itself where you can, so the number you are entering is the number in your hand, copied by eye rather than from memory. Then save the registry's contact route in the new phone, because the next amendment, an address after a move, say, should not start with hunting for how to reach them.
Hunting Down Every Copy of the Old Number
A phone number rarely lives in one place. Hunt down the repetitions and update each one: the file her vet holds, the details on her collar tag, any note left for sitters or family, and the contact in her scannable profile. Each stale copy is a separate dead end waiting for the worst day. Check the second contact person's number too, by actually ringing it, since that backup route is worthless if it quietly changed last year as well. If your old number still works during a handover period, keep it answered until every copy is replaced, then let it go.
Family phones deserve a pass too. If your partner or a parent is listed anywhere as an alternate route to you, check the number recorded for them has not changed in the same season. Numbers in a household tend to change in clusters, new contracts and new handsets arriving together, and a backup contact with a dead line is decoration, not backup.
Testing the Route a Finder Would Take
Keep a note of the date you made the change, with the old and new numbers, in her file. If a call about her ever goes astray, that dated note lets you work out which version of the record the caller saw. After a month, when every copy has been replaced and tested, the note can shrink to the new number alone.
Finish with a rehearsal. Ask a friend to read the entry as a finder would: chip number first, registry lookup second, dial third. If any step stalls, fix that step rather than assuming goodwill will bridge it. Remember that updating her collar profile does not amend the registry, and amending the registry does not refresh her profile; both jobs are yours, and both are quick. Maintained through KinsLe whenever your details change, her Verified QR ID Pet Profiles record shows callers the number you use now, matched to the registry entry you checked.