Are your clowns currently hosting in it? Is a larger tank an option? I fear that getting a smaller one will put you back in the same spot in a few months as carpet anenome are know to grow.
As for removing it if it has to go just work your hand underneath and gently work it off whatever substrate it is attached to and then bag it for transport. Make sure your LFS
is ready and willing to accept it as well.
If it is firmly attached to some rock you may have to wait of give up the rock. If you are worried about the sting I would not, just make sure you handle it from the underside as much as possible. You can also use a new rinsed pair of rubber gloves as well.