February 2019
Sometimes I found no one donates to me (esp rare cards) so it will be better if I can cancel my request and make a new one without being punished by cooldown.
Also you should increase the rewards when giving out a rare cards it seems now people are unlikely to give them out.
Maybe an exchange system, whenever you request a rare you put one of your rare in and when someone fulfills he gets the rewards plus the card you put in.
February 2019
Agreed. You should be able to cancel your request, as long as you have not received any cards yet.