Proofread/ modifications requested

Attention: Language coaches. Please help me make the application below grammatical and more formal.

[Body]
Sub: Change in beneficiary.
Sir,
I request you to change the name of beneficiary which I had stated as ABC (Brother) while opening an account in this bank. I want the beneficiary to be as Miss XYZ (wife). I will appreciate it very much if you consider my request/ application immediately. Thanks.

Faithfully yours
Noren
A/c Name: Limbu, N
A/c #: 123456789

[End of body]

Thank you very much for your help.
Noren

Is this
…"" I will appreciate it very
much if you consider my request immediately.""… worth writing or still some words need to be added? Please help. Thanks.