Dear

My next   [specify]   payment will be due on

Due to an unexpected emergency that has occurred, I will
be unable to make this payment by the  [date]  I am
requesting an extension of  [time]  to make this payment.

If you review my file, I believe you will find that my
payments have generally been made in a timely fashion.
My relationship with your bank is very important to me,
as well as my desire to maintain a good credit rating.

Thank you very much for your consideration of this request.