Yeah, I completely understand why you'd want more flexiblity with your tank. If the shark just doesn't fit in your plans, find it a good home.
A few thoughts on coral cat sharks... I have them and really enjoy them. However, they aren't for everyone. They are rarely active during the day, definitely a nocturnal species. I keep mine with a few large tangs, so I have something to look at during the day. But these guys have a considerable upside. They don't get too big, and don't require a lot of room, they are tropical species, so a chiller isn't a must, and they their adult size is realitively small. IMO, they are attractive species that are very well suited for life in a large home aquarium.