Romain Poite, the top French referee, has withdrawn from his match on Sunday because of illness and has had to be replaced.
Poite was appointed to referee the match between Edinburgh and Munster at Murrayfield.
Greg Garner of England will replace Poite. Garner, who refereed at the Junior Championship in South Africa in the middle of 2012, has been making a great impression in the Aviva Premiership.
Garner was appoiinted to referee the Heineken Cup match between Benetton Treviso and Ospreys next week. This week was down to be an assistant referee in the match between Toulouse and Benetton Treviso in Toulouse on Sunday. His place is taken by JP Doyle.
The referees for these matches are now as follows:
Edinburgh vs Munster at Murrayfield
Referee: Greg Garner (England)
Assistant referees: Cyril Lafon (France), Stéphane Boyer (France)
Television match official: Daniel Gillet (France)
Timekeeper: John Montgomery (England)
Citing commissioner: Alberto Recaldini (Italy)
Assessor: Les Peard (Wales)
Toulouse vs Benetton Treviso at Ernest Wallon
Referee: Wayne Barnes (England)
Assistant referees: JP Doyle (England), Robin Goodliffe (England)
Television match official: Graham Hughes (England)
Timekeeper: Bruno Bessot (France)
Citing commissioner: Matt Bayliss (England)
Assessor: Patrick Thomas (France)