Are you sure the tire is mounted backwards or is the wheel on backwards? The arrow on the tire should match the arrow on the wheel. If it does, just pull the wheel and turn it around.
Dismounting the tire and remounting it will not hurt the tire at all. It won't hurt your bike or the tire to run it backwards. The reason the tire is directional is because of the rain sipes. The sipes in the tire is designed to push the water away from the tire to allow it to get traction. Simple solution, just don't ride in the rain
Take it back and have the dealer correct it. Very simple and they will be happy to take care of it. Oh, and if they give you a new tire, please send me the take off and I'll run that puppy til it's as slick as a button
I accidently mounted one backwards once and I ran that thing out just the way it was. I don't like riding in the rain and I was aware it was backwards so it worked out fine for me.