Rule 24-1. Movable Obstruction

A player may take relief, without penalty, from a movable obstruction as follows:

a. If the ball does not lie in or on the obstruction, the obstruction may be removed. If the ball moves, it must be replaced, and there is no penalty, provided that the movement of the ball is directly attributable to the removal of the obstruction. 

b. If the ball lies in or on the obstruction, the ball may be lifted and the obstruction removed. The ball must through the green or in the hazard be dropped, or on the putting green be placed, as near as possible to the spot directly under the place where the ball lay in or on the obstruction, but not nearer the hole.

The ball may be cleaned when lifted under this rule.

New Decision for 2008 regarding rule 24.

Opponent or Fellow-Competitor Removes Obstruction Affecting Player’s Play.

Q: An opponent or fellow-competitor removes an obstruction that affects the player’s play. What’s the ruling?

A: If the obstruction is movable, when it is the player’s turn to play, his opponent or a fellow-competitor has no right to move the movable obstruction affecting the player’s play if the player requests the opponent or fellow-competitor not to do so. If the opponent or fellow-competitor ignores the request, he is in breach of rule 1-2. In match play the opponent loses the hole. In stroke play, the fellow-competitor incurs a penalty of two strokes.