Has your original return been accepted? You should wait until it's fully processed and you got the first refund.
How to amend an Online return
https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-turbotax-online-return/00/27577
Another way to amend is from inside your return. Open your return, you might have to select Add A State to get back into your return.
Then go to........
Federal Taxes or Personal (for H&B/Self Employed version)
Other Tax Situations
