I'm not familiar with this Nortel Norstar system, but after poking around, I found Feature 4 will call forward to another extension, but I'm wondering, can you call forward to an outside phone number? We want to call forward all calls to another office if possible.

We have an office in the San Bruno, CA area, and they will move in with our San Francisco office temporarily, and as a backup plan, we are trying to figure out how to use the phone system to forward calls, if the carrier order doesn't complete in time.
Thanks.

Simply have your carrier install call forwarding on the 1st line if it's not already there. Then engage it to forward the calls to your new office number.

Above mentioned is preferred using the carrier because it is simple, press line 1 and the * code....done.
If you want the system to do it then it will tie up lines like a conference and have less volume.
Both Software 4.1 and a tech to program it required.

Curlycord is 95% correct. Sometimes it will have less volume and may be hard to hear and it ties up two lines.

But it does not have to be 4.1 software.
It has to be at least 4.1 or higher.
And you have to use routing.

It is best to call a tech to set it all up. Then you can forward on demand.