Wix Booking - Transfer App?

So I have a client who started creating their own cabin rental website on their own. They said they paid for the Wix Booking app, but have gotten confused and lost in design. They now want me to create a site for them. When I look at the site they published and click on the Book Now button, an error comes up from iRoomi (she is not sure what that is since she says she has Wix Bookings). Anyway question is, if she had already paid for the Wix Booking app on her current site, can it be transferred to a new Wix site I create and transfer to her account? TIA This will be the first rental site I have designed. I would love to know a b it more before I actually get more involved.