Dear Felix
Regretfully, unfortunate circumstances have caused us to write this letter to you.
We are writing to inform you that you are in default under our security agreement of [DATE, ex. January 5, 1998] for the following reason {s}:
[LIST REASON (S), ex.
Failure to pay second installment of $12,000 per clause 4(b)]
As provided in our security agreement, we hereby request and demand that you surrender possession of the collateral listed therein to us immediately.
Regards
Lydia