how to switch between 2 GV lines?

[xanatos]

I have 2 google voice lines set up on my obitalk.
Sometimes when I am talking on one of the lines, I can hear some sounds that indicate someone has called the other line. When this happens, how do I switch to the other line?

[RonR]

If you get a Call Waiting signal while talking on one trunk, simply push the FLASH button on your phone or briefly depress and release the hook-switch.

[xanatos]

hi, I tried press flash but it did not switch to the other line, so that's why I posted my question.
Isn't flash only supposed to work in the case where someone calls the same line that you are already on?

My case is different, because I am talking on GV line 1, and someone is calling GV line 2, which is a completely different number.

[RonR]

It should work under all circumstances (it does here).