Final answer:
When notified by the Linesman of an icing infraction that was missed before a goal was scored, the Referee should disallow that goal and reset the game to the state before the mistake, including reverting the score and conducting a faceoff.
Step-by-step explanation:
If a goal is scored in an ice hockey game but before the play resumes, the Linesman notifies the Referee that the play should have been called for icing, the Referee should disallow the goal. Icing is a rule that is meant to prevent teams from simply shooting the puck down the length of the ice to avoid playing it. If the Linesman indicates that icing should have been called, the play is considered dead before the goal was scored. The proper procedure would be to reset the game to the situation before the improper allowance of the goal. This means conducting a faceoff in the appropriate zone according to the icing rules, and of course, the score should revert to what it was before the goal that is now being disallowed because of the icing infraction. This kind of situation requires the Referee to work closely with the Linesman to ensure the game is played under the correct rules, and to maintain the integrity of the sporting event.