You really need to get alterations done by the artist themselves, getting someone else to do it without permission from the artist you're opening yourself up to various legal issues. For example the person doing the work would have to own the item too because it would be illegal for you to give it to him (distribution), and for him to give you the altered copy would be again a big no no because he has no rights to distribute it to you. It's a huge kettle of fish you don't want to get into, it's best to wait for a reply from the artist.
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