Updating Pcell Parameters through script

Hi,

I am using PCells for my design. So I am setting some parameters for all the pcells.

Letus say I am using finger width as 10microns. and some others parameters( gate width, fingers, contacts..)

 So When I am trying to modify these parameters using change properties form in GUI it is working fine.

But when I have tried to modify using script, the parameter values are setting as like in gui. The cell is not looking like the one which I had done using gui. and If i modify anything(any parameter) then these two are looking similar 

I am using the script like this say my pcell is pch_mac, I will select that and 

geGetSelSet()~>wf = "10"  ;(this is finger width)

geGetSelSet()~>nf  = "2" ;(this is fingers)

So my question is whether we have to say apply these parameters after setting all or is there anything like refreshing ?

I hope you understood my point..