Turning down recommendation

[eaae]

Hi!
I recently e-mailed a teacher about meeting to write a recommendation, but she seems busy. Another teacher told me she could write a recommendation, so how should I tell the other teacher that I don't need a letter of recomendation anymore? I don't want to sound rude.
Thank you!

[Barb_D]

Dear Ms. Smith/Mr. Jones,
Thank you so much for your offer to write me a letter of recommendation. As it happens, I have already completed the application that required the letter, so I do not need a letter at this time. I hope I may keep you in mind for a future reference, if the situation arises. I truly appreciate your generosity.