Antony Gautier issued one of the quickest red cards in the history of UEFA Europa League in the 2nd minute of the play-off tie between AZ Alkmaar and Atromitos. However, the procedure how he took this decision is remarkable: At first, he only issued a swift yellow card, then changed his mind after having seen the fouled player's injury, turned around and sent off Alkmaar's Henriksen with a red card.
The Laws of the Games define:
"The referee may only change a decision on realising that it is incorrect or, at his discretion, on the advice of an assistant referee or the fourth official, provided that he has not restarted play or terminated the match."
Gautier did not restart play and was thus allowed to change his mind. It is hence possible to correct his own decision in terms of disciplinary sanctions, even after having seen and assessed the injury of the player who was fouled.
But certainly, he totally failed in selling this decision to the players. Instead of pointing to the injury of the player, he could have walked out to his assistant referee to express that there has been a conversation between them. This would in a way legitimate his decision on the pitch and would not undermine his authority. The way he behaved in this decision process is, at any rate, not adequate.