I use Ooma VOIP service and you can forward calls to a different number (I use that occasionally). I don't use it but they also have an iOS / Android app which lets you make calls from your Ooma VOIP number. The FAQ says you can't call 911 with it, so that's smoke anyway.

https://support.ooma.com/home/ooma-app-faq/#can-i-make-emerg...