Since your return has already been processed and you received your refund, amend your return and make it the joint return you want to file.
https://ttlc.intuit.com/questions/1899507-how-do-i-amend-a-separate-return-to-married-filing-jointly
**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.**
