My extension was accepted but I realize I made a mistake on it by putting 0 on tax liability. I will be getting a refund so I thought tax liability would be 0. Can I correct this? Everything is 0 excepted for the amount that has already been paid in.
There is no amend to an extension. An extension only extends the time you have to file your return, so as long as you put the correct information on your return, you will be OK. Any taxes owed must be paid by April 15, 2019 to avoid a penalty & interest.