Apology For Delay Shipment

Grammar Pattern
[Date]
[Addressee]
Dear [Name]:
This is to inform you that we are unable to make delivery
on the above referenced purchase order on the date
indicated.
We should have our merchandise ready to ship within [#] days
of the original delivery date and we hope that you can hold
off until that time.
We did want to inform you of this delay as soon we were
advised in order to give you as much time as possible to
make alternate arrangements, if necessary. We can assure
you, however, that if your order remains in force we will
expedite delivery to you as soon as we have received the
merchandise.
Please accept our apology for this delay and thank you for
your understanding.
Yours very truly,