Barn

Rules
Move any one of your existing settlements to a hex of the same terrain type as your played terrain card. Build adjacent if possible.

FAQ
Adjacency is checked when placing the piece

Check for eligible hexes adjacent to any of your settlements on the map after you pick up the settlement to move. E.g. if you place 3 settlements together on 3 canyon hexes and now have no settlements adjacent to any canyon hexes, and then you pick up one of those settlements with the Barn, then you have to put the settlement right back on the hex it came from, since that is an empty canyon hex next to one of your settlements.

No compensation for being unable to use an action tile because terrain is not available

In the unlikely case that there are no remaining empty hexes of the card's terrain type, then you cannot use Oracle or Barn that turn. You do not draw a new terrain card as you would if there were no remaining empty hexes during your mandatory 3 card placements.

Strategy
Remove the only settlement touching the Terrain of your actual card. Then place it freely on the board.