I have deployed my own network of blockchain that is based on the ethereum network. I wanted to know if one could change the currency used to pay for the gas on the private network.
AFAIK there's no easy way to do this. The ethereum protocol is designed to use its native currency for gas.
It would probably be very difficult to alter the protocol to run on an external currency. And it's probably impossible to allow any foreign currency, since external currencies have a potentially endless variety of implementations.