If you made a mistake while doing your taxes, you may or may not have to amend your return.  

If you have already filed your tax return, wait to see if it gets accepted or rejected. If it is rejected, you can go back and make corrections before you re-submit. If it is accepted, you can no longer make changes and will have to file an amendment to correct any mistakes.

See below for information regarding amending tax returns - https://ttlc.intuit.com/replies/3288565