so I found the soultion
in order to use the Ports number 0 and 1 for a VC instead of 2 and 3
you need to run the following commands
root> request virtual-chassis vc-port set pic-slot 1 port 0
root> request virtual-chassis vc-port set pic-slot 1 port 1
root> request virtual-chassis vc-port delete pic-slot 1 port 2
root> request virtual-chassis vc-port delete pic-slot 1 port 3
now you can use the ports 0 and 1 for VC