Tournament rule 509.4
At high OPL, a player can reverse their most recent action and make a different decision for that action (including not taking it at all) if no new action has been taken by either player and the following is true:
- 509.4.a The player wants to make a different decision for a spell or ability immediately after all choices have been made and…
- 509.4.b The player wants to make a different decision for playing a unit or gear immediately after playing it to a location…
- 509.4.c The player wants to make a different decision immediately after making a choice such as moving a unit to a location or…
- 509.4.d The player wants to undo a decision to exhaust or recycle runes.