Grade Change-Graduation is on hold. Please HELP

I have decided to write an email to the dean for my grade change. I asked the professor and he was willing to do it first but when he realized the Dean and department need to approve it he did not want to do it. I know it is up to Professor whether or not my grade will be changed but I am pretty sure he will be OK if I get approval from the dean.
I got a C- on this class and Ineed to pass it in order to graduate .
I can’t take that course this semester since it is already full. I really need some help!
I like you guys and your opinions. I’d appreciate some feedback on what I have written so far.

Thank you very much!!

Dear Dr. Dean Name,

I am “my name”, a senior “my major” student. I would very much appreciate your input concerning a matter pertaining to a grade change in “blah blah” class.

I had a C- (with a 69.7% final grade) and my intent to graduation is on hold. I kindly asked “professor name” if a grade change was possible. At first, he was willing to change it and asked me how he could change my grade to a C. However, when I sent him the information on how to do it he did not really want to change it since it needs your approval.

My question is, if he wants to change my grade to a C, would you kindly approve it?

XX course for this semester is already full and there are 7 people on the waitlist. I probably won’t be able to register it untill summer, which will delay my graduation for 8 months.

I know this is really asking a lot , but it would make a huge difference to my life if you could sincerely approve it.

Sincerely,
My name.