Cloning VM question

Hi all,

Host Fadora17 64bit
VM Debian 6.0.6 64bit size 12G vm01

I’m prepared cloning vm01 to create a new VM but expect expanding its size to 20G. vm01 is just created untouched. I’ll use it as source/basic VM cloning new VM for testing. Please advise is there any way doing it? TIA

B.R.
satimis