Possible to change voicemail number?

[Trig8]

I have been trying to change the voicemail number on my unlocked s620, but all I get is "reserved".
Any ways around it?

[jeonatl3]

It seems OK for me in Settings > Call Options > Voice Mail Number and just enter a different phone number there :-)

[Trig8]

Thanks! It worked!
I am new to WM smartphones as you probably would guess....