Replying to Looking for some advice from ski-graphic designers

Yo, I recently designed some graphics for a small ski company. I know them personally so I haven't been too stringent with making sure everything's copyrighted. I'm quite new to this type of thing, and don't really know how to protect my art but at the same time be as cooperative as possible with the company.
As it stands right now, they want me to send them the original art so they can play around with it. I'd like to see them get graphics they're happy with, but I also like my art the way it was originally designed.
What's got me confused is if I should ask for any kind of payment in order for them to manipulate my art. Depending on the changes they make to it, I may not want to have my name used in conjunction with the art. I'd really like to see this company get some sick graphics, but I also don't want my original design to be misrepresented.

Thanks