Form 1120S U.S. Income Tax Return for an S Corporation is amended by checking the Amended Return box located at the top of Page 1. This checkbox can be accessed through the Q&A by following these steps:

1. From within your TaxAct® 1120S return, click Filing. On smaller devices, click the menu icon in the upper left hand corner, then click Filing
2. Click Amend Federal Return (Desktop users, located directly below the tabs)
3. Enter the information as requested on each screen to prepare the amended return

You will need to attach an explanation of changes, and if the income, deductions, or credits changed then a new Schedule K-1 must be filed and copies sent to the shareholders.

Starting in 2014, TaxAct supports the electronic filing of amended S Corporation returns. At the end of the Amended Federal Return section you will be prompted to select either Paper Filing or Electronic Filing.  

Before mailing the return(s), be sure to review the paper filing instructions.