Ask the person you purchased the design from as they would be able to unlock it and you won't need to worry about copyright issues. The one that digitised the design may appreciate the idea.

Very cute bag!!

Like rescuer I would say ask her. If you are on facebook this would be the easiest way (> DisorderlyThreads). She has posted this in some facebook groups so I think there you would get a quick reply. Most of the digitizers are so helpful if you have a question or need an extra :o)
Greetings, Bettina
PS: Maybe it will be a little stiff with a satin stitch around the roof of the tower. Maybe a diamondstitch will be a better option? Some designer offers now an update on older designs with a straight stitch so the fabric don't fray.

I have seen this bag in one or more of my embroidery groups on FB. I agree, contact the digitizer and ask her about it. She may appreciate it more than you know. Perhaps she is unaware of this issue when using cotton instead of felt. Let us know how you make out. It really is an adorable little purse!
Meri

Update--I did contact the digitizer, and she replied that due to time constraints, she does not make changes to designs. What to do now? Btw, the bag stitches out beautifully.