You can move it, or create a new one at the new location and remove the old one, or recycle them in a loop. Not sure if building is asynchronous or not, Alternatively your pawn character could just collide with the surface it is running on, and you may not have to use a navmesh, Navmeshes are mostly for AI. More info here: https://docs.unrealengine.com/latest/INT/Engine/AI/BehaviorTrees/QuickStart/2/