The doctor who performed an endoscopy on Joan Rivers before she went into cardiac arrest has stepped down as medical director of the Manhattan clinic where she was treated and he is no longer doing procedures there, the clinic announced on Friday.

Ms. Rivers, 81, the comedian, had what was supposed to be a routine procedure at the clinic, Yorkville Endoscopy, on East 93rd Street, on Aug. 28. She stopped breathing and went into cardiac arrest before emergency medical workers were summoned by a call to 911. She died seven days later, after being taken off life support.

The doctor who performed the endoscopy, Lawrence B. Cohen, a prominent gastroenterologist, had brought an ear, nose and throat specialist into the operating room to examine Ms. Rivers, even though that doctor was not authorized to practice medicine there, according to people briefed on the matter.

On Friday, a spokeswoman for the clinic said in a short statement to reporters, “Dr. Cohen is not currently performing procedures at Yorkville Endoscopy; nor is he currently serving as medical director.” There was no elaboration.