The closing message.
THE TONE
Gracious. They may return, and they will certainly be asked about you.
WHAT TO INCLUDE
Confirmation of the leaving date
What you are providing: a full backup, DNS records, domain transfer if applicable
How long the account will remain before termination An offer to help with the migration Any outstanding invoice
THE GRACE PERIOD
State it. "The account will remain active until the 30th, in case anything was missed."
Costs you almost nothing and prevents an awkward later request.
WHAT NOT TO DO
Ask them to reconsider at length Express resentment Delay providing anything Terminate on the date without warning
ASKING WHY
Once, briefly, and accept the answer.
"If there is anything I could have done better, I would genuinely like to know."
Some will tell you something useful.
THE FINAL PRACTICALITY
Provide the backup before the leaving date, not after. A client chasing you for their data afterwards remembers that.
WHAT THIS BUYS YOU
A former client who speaks well of you, in a market where reputation travels.