If you have the motherboards owners manual you can look in there to see what the instructions are to do that. If your board has the dual bios then it's usually a jumper setting on the MB that switches to the other bios chip. If your familar with jumpers there should be a three pin connector right next to the bios chips and there should also be a led to show which bios chip is being used. That three pin connector will have a jumper on it that connects two of the pins , you simply take that connector and slide it off and onto the the opposite pin. The middle pin will have the connector in both settings and it's the end pins that are switched. The diagram in the owners manual will show you how that's done.