If you already e-filed and used a filing status that you want to change, you will need to wait until the IRS has fully processed your original return. Then you can amend to change your filing status if necessary. It is not clear what you are wanting to change from or to. You will not be permitted to switch from a joint return to married filing separately after the filing deadline on April 15.
If you need to amend to switch from a married separate return to married filing jointly:
https://ttlc.intuit.com/questions/1899507-how-do-i-amend-a-separate-return-to-married-filing-jointly
You need a Form 1040X which is not yet available. 1040X becomes available later this month.
**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.**
