I was curiosing around and found out that I have a quest for Merana 'open' for a pet. The problem is, I don't remember which pet I was trying to do that for and I'd not like to give her all the ingredients and lose a pet color that I already have as I desire it.
Is there any way to cancel? Is it possible to ask some kind of moderator to do that for me? Is it even possible?
It kind of bothers me to have this like that and there's not a cancel option. Plus, I might one day want to use it on another pet and this quest is already open for an specific pet, I just don't know which one and not sure if I should take the risk to give her the items and find it out.

Unfortunately there's no way to cancel it officially. I've heard people were able to cancel quests in the past but since I'm not sure if using this method is against the rules I won't give out any details here. What you could try though is making a ticket, hopefully a User Admin will be able to tell you which Pet is on your Merana quest. Good luck!