The Diplomatic No

Decline a request while protecting the relationship.

Prompt

Write a short email declining [request] from [person, relationship, e.g. my manager / a client].
Reason (be honest but brief): [reason].
Offer one alternative: [alternative or 'suggest one'].
Tone: warm, firm, no over-apologizing. Under 120 words. Give 2 versions: one more formal, one more casual.

Tips

Remove any 'sorry' it adds more than once; one apology is plenty.

Example output (excerpt)

"Thanks for thinking of me for the Q3 report. I can't take it on this month without delaying the launch work, which I want to do well. I could review a draft on the 20th if that helps."