Letter to Bank For Mobile Number Updation-
The Bank Manager,
<branch name and address>
Sub: Request to update my registered mobile number.
I have a SB account with your concerned bank here. When I opened my account, I have given you the mobile number <old mobile number> which I am not using presently. So hereby I request you to update my registered mobile number with this new one, <new mobile number>. Please change it as soon as possible so that I can do my regular transaction easily. I have given below all my details related to my SB account.
Saving bank Account Number: <your bank account number>
New Mobile Number: <your mobile number>.