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So can I still amend my tax return to remove the SSN of the child dependent & refile?

Would I have to pay again or also send in the amendment by mail? I already received my refund but don’t want to touch the money in case I owe anything back per the adjustment. 
If we decide to amend my tax return by adding both of our kids onto my amended tax return, do I then need to add the rest of the mortgage interest and property tax that was originally split between us?