Dear :

Thank you for your letter of [date] requesting quotation for [project]. The project is certainly very attractive, and we are eager to offer our services. May we have an additional week to work on the specifications? We should be ready to review our bid with you by [date].

Please give me a call as soon as you see this letter. I will call you tomorrow to make sure that the extension is acceptable.

Thank you again for inviting us to bid.

Sincerely yours,

[name]

[title]