How do i change the bank account information on an amended return

Amend return refunds are not deposited. The IRS takes up to 16 weeks to process and those are sent via mail. Be sure your address on your tax return is correct.

16 weeks my butt its been 7 months still no return

@darrin_broshears you mean no refund?  For an amended return or an original return?  Amended returns can only be mailed.

And you get a check in the mail for a refund from an amended return--not a direct deposit.

It is always possible IRS did not receive your mailed return.
It is now possible to check your status. See here: https://www.irs.gov/filing/wheres-my-amended-return