Rivers, 81, was rushed to Mt. Sinai hospital in critical condition after she stopped breathing while undergoing surgery at the Yorkville Endoscopy clinic.
E!, where Rivers hosts Fashion Police, has reported that she is in stable condition.
Rivers' publicist has not responded to USA TODAY's request for comment.
Rivers has been busy promoting her latest book, Diary of a Mad Diva. She was scheduled to make an appearance Friday in New Jersey. "I don't go out as much as I once did," Rivers told the Asbury Park Press. "But I still go out and perform. I love it. I'm never going to retire. Why would I?''
In an interview with USA TODAY in July, the legendary comedian said, "Life is tough. Life is tough. I just think, 'Make them laugh.'"