The NI seller requested an License transfer on November 18th at 23:00 Texas time, but there has been no response yet. How long does it take?
It depends.... Sometimes it takes several hours, sometimes several days.
Also, you have not said, if the seller has used automatic Licence Transfer system, or if he had to do it using Support Ticket... In that case (and at time of NI Sale), it might take even longer.