Should a ref enter a changing room after a game is over to give a card to a player or should he inform a club official he is going to report the player in his match report

USSF answer (January 5, 3012):
Under normal procedure, the referee must inform the player of his decision at the moment of the misconduct (whether a caution or a dismissal), rather than dithering about and waiting till the players had entered the changing room. Why? Because the Law forbids the referee from changing a decision once he has declared the match to be ended and the referee in this case clearly did not make the decision until the match was over, a dreadful mistake.

In this case the referee could tell a team official, if one is available outside the dressing/changing area, but there is no need under the Law for the referee to enter the changing area. The referee simply gives the team official the information and then sends a full report to the appropriate authority within the specified time limits. However, because of the mistake the competition authority may refuse to deal with the matter at all.