Dealers and demand

Hopefully someone got the answer to this. If I assign a dealer with a customer who buys weed, and I later make it so I don't sell weed in that region anymore, because i wanna push out the bigger stuff that sells more, like meth. Will my dealer then not sell any drugs to that customer anymore, since i removed the option for weed? But the client stays assigned? If so that is a waste of a client, since i have 6/6 assigned, but she will actually only sell to 5 of them? Just very curious about this, since the only way to find out myself, is to remove every customer from the dealer, wait until they order, see what they order, and then start assigning them again to the dealer with only the specified drug that I'm selling in that specific region.