How can I change my filling status from married filling jointly to separated?

[VolvoGirl]

Did you already file a Joint return or are you preparing your return now?

[Jamie CPA]

If you already filed, you have until the due date of the return to amend it.  If you don't amend it by then, you can't change the status from MFJ to MFS.

[VolvoGirl]

It is now too late to amend Joint to MFS for any year.  You had to amend by April 15.

[Jamie CPA]

Correct!  Even if an extension is filed, I don't believe you can make this change after the April 15th deadline.