Istanbul
What happens if I cannot or do not want to pick up or leave an Assistant at the place I moved to?
The rulebook says the turn ends immediately in this case, with the Fountain as the sole exception.
Your turn ends immediately after the move: no action, no payment to other Merchants, and no encounters with the Governor, Smuggler or Family Members. The only exception is the Fountain, which needs no Assistant. A Merchant with no Assistants in his stack can still travel, but can act only at the Fountain or on a place where one of his own Assistants is already waiting.