bool LeaveParty ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & LocalUserId, const [FOnlinePartyId](API\Plugins\OnlineSubsystem\FOnlinePartyId) & PartyId, bool bSynchronizeLeave, const [FOnLeavePartyComplete](API\Plugins\OnlineSubsystem\Interfaces\FOnLeavePartyComplete) & Delegate )