How do I give role(Master or Slave) to nRF51822-based BLE module ?

[t-kanda]

I would like to use nRF51822-based BLE module as Master role or Slave role. How do I give role(Master or Slave) to nRF51822-based BLE module ? What should I use ?

I ask for your consideration on this matter.

Sincelerly, t-kanda