Nokia 6300 dialing 186 for Voicemail-1, can this be changed?

[Edward2]

I'm trying to setup a 6300 on Ultra Mobile, but holding the '1' down dials 186.

Ultra mobile's website indicates hold down '1' or dial 123 for voicemail.

Any suggestions appreciated.

[Edward2]

So I've been working with Nokia tech support.
They're saying the #1 - 186 is permanent, can't be changed.

When you go into the speed dial numbers, the #1 can be seen with 186, but is grayed out (can't be changed). So I assigned my VM access #123 to speed dial position #2.