Dear Sir or Madam:

We have a very uncomfortable request - we are asking for an extension of time on our bill for __________.

We had been depending on a check from one of our clients to cover this bill. However, we have just been informed that this check will not arrive until _______________.

Therefore, we must ask for your indulgence and grant us a two weeks' extension of time on our bill. We are sorry about any inconvenience this may bring to you.

Respectfully,