bq25890 - "PUMPX_UP" and PUMPX_DN of REG09

Hi all

Would  you mind if we ask bq25890?

Could you let us know what the fucnction are PUMPX_UP and PUMPX_DN?
We recognize as follows;

-PUMPX_UP : 0 – Disable, 1 – Increase VBUS
-PUMPX_DN: 0 – Disable, 1 – Decrease VBUS

If we set PUMPX_UP/DN 1, does VBUS increase/decrease automatically(5V->12V, 12V->5V)? 
Or, step by step using register setting?

Kind regards,

Hirotaka Matsumoto