Changing Main hard drive

Right now I have a 120gb disk and a 60 gb disk. The 60 gb disk is currently the MAIN disk and is close to full because a lot of programs will only go on the MAIN disk. How do I change main boot disks?

I assume you have nothing you want to keep on the second drive

If that is the case, use SuperDuper to clone the contents of the boot drive to the bigger one

Then select the bigger drive as the start-uip drive using System Preferences > Startup Disk

OK it all worked perfectly thanks!

Now how do I change disk name? MAIN is erased and PARTITION B is the new MAIN. What to do? The disk utility doesnt seem to have a name changing function.