Plan for the ordinary replacement
Use a fictional note for the check. Once the new phone works, revoke the old device and verify that it can no longer access live records. Treat its downloaded files as a separate cleanup task. If the old phone was lost or stolen, revoke its access promptly instead of waiting for its replacement. While the old phone is safely in your possession, confirm the new phone can use the supported sign-in or pairing flow. Test a private and a shared sample under the correct account. Compare the result with another adult's authorized view.
Handle loss or theft differently
If the old phone is missing or in someone else’s possession, do not wait for a successful migration before revoking its access through the available controls. Follow the device provider's recovery process as appropriate. Revocation can stop future service requests; it does not remotely remove every file the old phone already downloaded.
Close the transition
Once the new phone works, review the list of authorized devices and label the current one clearly. On a device still in your control, remove downloaded documents and sign out of other household services before passing it on. Keep the new pairing code or recovery secret out of shared chat history.