It sounds like what you really did-- if in fact you did it today on 10-29-19 -- is make a mess of your already filed tax return, You need to change it back to EXACTLY the way it looked when you filed it originally. You will need to amend your tax return, but you cannot do that yet.
First, you have to wait for the return to be fully processed before you amend. AND the system is now in transition from 2018 to 2019 software. You cannot do anything "new" online now. You have to wait until later in December when the transition is complete and then you can prepare a Form 1040X to amend your 2018 return. And as already stated, you must be able to work from that original return exactly as it looked when you filed the return.
And amended return has to be printed signed and mailed. It takes the IRS about 4 months to process an amended return.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
