If your efiled return has been accepted you have to file an amended return. This FAQ explains how to file an amended return.
https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-...
If your efiled return is rejected you can just add the schedule c to it and then try to efile again.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
