Joan Rivers (Getty Images)
Rivers had a New York rager planned for 300 pals on Wednesday evening, but reportedly scrapped the celebration to mourn her sister, power attorney Barbara Waxler.
While the cause of death is unknown, an obituary for Waxler states that she died "surrounded by love ones." The family asked, in lieu of flowers, donations be made to children's causes.
As for funny lady Rivers, she simply posted a vintage photo of Waxler to Twitter, with a message to rest in peace.
No word on if the event, to be held at Manhattan’s Metropolitan Club, will be rescheduled.
Rivers, a bestselling author, books standup gigs in New York and the surrounding area frequently. She also serves as host for the E! network's embattled "Fashion Police."
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