I read about "Ardell's Unread" but never tried it.
The only thing I know I would use is Black2Natural or Aveda products. If you don't have time to receive by mail before the wedding run to an Aveda hair salon and tell the hairstylist you want to get rid of the red he/she will probably suggest you to try Blue Malva or Black Malva I got both and they work well.
Hope this helps,
Dan.