When a piano is moved, the move itself will not knock a piano out of tune, unless, of course, it is jolted or dropped. However, after a move, a piano will go through some changes that may cause the tuning to vary. These changes will occur over a 2 to 4 week period after the move. If possible, it is a good idea to wait until these changes have taken place and are finished before you have your piano tuned. This acclimation process occurs because of atmospheric variations and can happen even if you only move a piano across a room.