For all competition matches, the home club has the first choice as to which of its official playing attires announced on the playing attire approval form it wears for its home matches. The clubs agree on the colours to be worn from the playing attires announced on their playing attire approval form. If the clubs are unable to agree on the colours to be worn by their teams, they inform the UEFA administration, who takes a final decision.
For matches in the UEFA Champions League path group stage, teams are asked, whenever possible, to wear the playing attires chosen by their senior teams for the corresponding UEFA Champions League match. The playing attires chosen can be changed at the request of the clubs provided the alternative solution does not lead to clashes in any part of the attires. In all cases, the UEFA administration takes a final decision.
As of the semi-finals, the UEFA administration makes proposals for the playing attires to be worn. The proposals can be changed at the request of the clubs provided that the alternative solution does not lead to clashes in any part of the attires. If no agreement can be found, the UEFA administration takes a final decision.
In any case, if the referee notices on the spot that the colours of the two teams could lead to confusion, he decides on the colours, after consulting the UEFA match delegate and the UEFA administration. As a rule, in such cases it is the home team that has to change colours, for practical reasons.