Please accept my sincere apology and you have our assurance that this will not occur again.
I must apologize for my error.
Please accept my sincerest and most heartfelt apologies due to my lack of attention on this matter.
I am writing to apologize deeply for what happened this morning as a last minute problem appeared suddenly.
Mary is out of the office this week and she will return next Monday. I must apologize that you were not told before.
I need to apologize as I cannot be in the office Monday so I am incapable of joining the activity that is happening.
Could you please check the contract to see if there are any problems?
This is the information you asked for and I have attached it for your reference.
I have attached the document for your signature.
I have attached the marketing proposal for your review.
Would you be able to review the attached contract?
May I know if you have any opinions about the sample products?
May I have your advice about the new price?
Would you like to add anything to the contract?