回复：如何能合法的赶走租客？

in my state (not NY), since there is no contract, he is your guest, you can let him go anytime you want. find a time when he's not around, put all this belongings to garbage bags, leave them in the front door step, and change the lock. that's it. If there is a trouble, call 911, you can even get a temp. restraint order against him on the spot.