Find out early
Watch for bounced emails, out-of-office replies and a new name on a ticket. When you see one, tag the account and tell whoever owns the relationship. Do not wait for the renewal conversation to learn that your main contact is gone.
Introduce yourself first
Write to the new admin before they have a problem. Say who you are, what the account has and how to reach support. One short, friendly message is enough, and it works better than a long welcome pack.
Rebuild the context
Pull together what the new person needs: the plan, the users, the integrations, any open tickets and the last few things that were agreed. Send it as a short summary. They should not have to read a year of tickets to learn what their company already set up.
Check who has access
Ask who the admins are now and remove anyone who has left. Confirm billing contacts too, so invoices do not go to an inbox nobody reads. Use your normal identity checks before you change anything on the account.
Offer a short walkthrough
Offer thirty minutes on the parts they will use. Record it if they agree and send the recording with a one-page summary. A new admin who feels competent in the first week is far less likely to question the purchase.
Record the change
Update the account notes with the new contact, the date and what you sent. The next agent should see the handover without asking.