Getting our company 1,000-seat license assigned to ME for an upcoming event

I have my own 500-seat webinar license - but I need a certain upcoming event on October 4 to use our company's 1,000-seat license (email hidden). How do I make sure that my event is pointing there AND how will I be able to log into that at the event time?  We make our events in CVENT which integrates with zoom.