There are times one one has more phone numbers than one can handle or when one needs to make sure one can receive calls on a number even when the phone’s battery died or there is no network coverage.

This is where call forwarding comes in – where for a price (the forward is taxed as an outgoing call) incoming calls can be sent to an alternative phone number…

I make the assumption that you’re running PHP 5.3 (the currently newest PHP version officially available in CentOS 6) or perhaps PHP 5.4.

The switch can, theoretically, be done on live system – just prepare yourself for a bit of hiccups here and there (or perhaps even serious downtime).