PLEASE CANCEL OUR ORDER
Regrettably, I must request that our order [ORDER OR ORDER NUMBER, ex. for 50 8x5 sheets of drywall] be cancelled immediately. [BRIEFLY STATE REASON, ex. As you know, the recent trim-carpenter strike has delayed construction and we will not require the drywall until the matter is resolved.]
Please accept my apologies for any inconvenience this may have caused you.