Rule 3.2b
Concession
Also searched as: gimme, conceded putt, conceding a hole, that's good
In match play you may concede your opponent’s next stroke, a hole or the whole match. In stroke play there are no concessions.
A concession is made as soon as it is clearly communicated, in words or for example by knocking the ball away. It cannot be declined or withdrawn. A conceded stroke counts as if the opponent had holed out with the next stroke.