15-1. General
A player must hole out with the ball played from the teeing
ground unless the ball is lost, out of bounds or the player
substitutes another ball, whether or not substitution is
permitted (see Rule 15-2). If a player plays a wrong ball, see
Rule 15-3.

15-2. Substituted Ball
A player may substitute a ball when proceeding under a Rule
that permits the player to play, drop or place another ball in
completing the play of a hole. The substituted ball becomes the
ball in play.
If a player substitutes a ball when not permitted to do so under
the Rules, that substituted ball is not a wrong ball; it becomes
the ball in play. If the mistake is not corrected as provided in
Rule 20-6 and the player makes a stroke at a wrongly
substituted ball, he incurs the penalty prescribed by the
applicable Rule and, in stroke play, must play out the hole
with the substituted ball.
(Playing from Wrong Place – see Rule 20-7)

15-3. Wrong Ball
a. Match Play
If a player makes a stroke at a wrong ball that is not in a
hazard, he loses the hole.
There is no penalty if a player makes a stroke at a wrong ball
in a hazard. Any strokes made at a wrong ball in a hazard do
not count in the player’s score.
If the wrong ball belongs to another player, its owner must
place a ball on the spot from which the wrong ball was
first played.
If the player and opponent exchange balls during the play of a
hole, the first to make a stroke at a wrong ball that is not in a
hazard, loses the hole; when this cannot be determined, the
hole must be played out with the balls exchanged.
b. Stroke Play
If a competitor makes a stroke or strokes at a wrong ball that
is not in a hazard, he incurs a penalty of two strokes.
There is no penalty if a competitor makes a stroke at a wrong
ball in a hazard. Any strokes made at a wrong ball in a hazard
do not count in the competitor’s score.
The competitor must correct his mistake by playing the correct
ball or by proceeding under the Rules. If he fails to correct his
mistake before making a stroke on the next teeing ground or,
in the case of the last hole of the round, fails to declare his
intention to correct his mistake before leaving the putting
green, he is disqualified.
Strokes made by a competitor with a wrong ball do not count
in his score.
If the wrong ball belongs to another competitor, its owner
must place a ball on the spot from which the wrong ball was
first played.
(Lie of ball to be placed or replaced altered – see Rule 20-3b)
(Spot not determinable – see Rule 20-3c)