Greyw

@Greyw90 haha, funny I was about to ask you if it was okay if I turned that char into an OC xD

But regarding your question, I found that it's completely up to the shop owner in their rules. Most other artists I have asked give approval and some other artists, like myself, have it listed in the shop rules that unless otherwise stated, the character in the premade is yours.

Hey!

Like others have eluded to, it is up to yourself on whether or not you allow customers to make OCs out of your work that they have purchased. However, if you decide that they cannot do this then you need to state this in your shop rules so that all customers are aware before purchasing. Although it's not strictly against the rules, you are entering tricky territory recreating a character that someone else has made into an OC, I don't think that it would be something that would be desirable for customers, and again you would need to state this in your rules. 

In future, if you do have questions please submit a support ticket, which can be found in the help section. Having a moderator answer your question over a member provides you with clarity that the answer is correct, whereas I wouldn't want you to receive an incorrect answer from a member (not to suggest that you have here) to then find out it was wrong down the line after you'd broken some rules.

Thank you for your answer @Pey, will definitely do that next time I have doubts .