How do you update the account number information after filling income tax return?

I had 2 account with me one checking and 1 saving later on i closed my checking account and retained saving. when i filled the IT return by mistake my checking acount number was used there which i want to correct now. I presume you are talking about the account number for direct deposit of your refund?

That's a tough problem.

Usually, there is little you can do except hope that you didn't accidentally put a real account number belonging to someone else on the form. If you put a non-existent account number down on the form, the payment will be returned to the IRS and the IRS will mail you a check in a few weeks. If you accidentally put a real account number down, you will be in for months of bureaucratic nightmares.

But call the IRS at 1-800-829-1040 and tell them what you did. See if they can help.