Jerry Seinfeld's Going Back to Opening Act Status ... for Margaret Cho

Jerry Seinfeld's headliner days are over, at least for one night ... he'll be the warm-up for Margaret Cho -- all to help her make good at the NJ comedy club where she bombed.

The Stress Factory Comedy Club fired off an email to audience members who were there for Margaret's disaster of a show on March 26th -- and it reveals that Jerry is on board for a make up show.

In the email, obtained by TMZ, Jerry writes ... "When a stand-up show doesn't go well, the audience and the comedian both go home unhappy, sometimes not really sure what went wrong. Every comedian has experienced this sense of unresolved resentment and anxiety."

He goes on to explain that he suggested to Margaret, "Wouldn't it be something if we could go back to New Jersey, back to that club with the same audience and try to make things right? Have a discussion where both sides - comedian and audience - could talk about what happened?"

Jerry adds he will "moderate" the discussion and then ... jokes will ensue. The show, which goes down Thursday night, is important to him "as someone who cares about comedy, comedians, and people who come to see stand-up."

Cool move on Jerry's part, and Margaret too ... considering how badly it went a few weeks ago.