How can you make an NPC move house?

Solution 1:

In update 1.1 they added a toggle to have house management. This allows you to set houses to certain NPCS and check to see if a house you built is viable. You can also see what NPCS own a particular house.

Solution 2:

You would need to

• Destroy his old house and build the other one (he will go to the new house when it becomes night if the distance isn't to far)

• Destroy his old house and build the other one and hope that the same type (merchant, gun dealer etc.) will respawn

We once had 2 merchants; when we tried to get a Demolitionist, we killed 1 merchant and got another 1; after we killed that one, we finally got the Demolitionist.

P.S. You only need to hammer away the chair and table to destroy his house

Solution 3:

If you click on the housing management icon
(the little house above the equipment slots)
you can then click on the banner for a living npc -
then click on the house you wish for them to occupy.

You may want to save and re-load the world,
if you don't want to wait for them to relocate themselves.