First you will need to wait and see if your return is Accepted or Rejected by the IRS. If the return is Rejected you can go back in and fix the mistake without amending. If the return is Accepted you will need to WAIT until you receive your refund and then Amend. If the return is from a previous year you can go ahead and Amend by clicking on the tax year below.

Follow these steps to amend:https://ttlc.intuit.com/replies/3288565