There are many good 2nd Line or sideline App providers in the play store, you might be using any of these for your business. But later you realized that you need more than just a phone number, like auto-attendant greeting, custom greeting messages like holiday greetings, etc.
So here are two options for you
Get another App like 9DiGITS which offers all the above service and starts with a fresh phone number. However, If you have already promoted your old number and printed Visiting cards, flyers, and other promotional material that can not be reversed then you can port number to 9digits.
I suggest starting with a fresh number as it instantly activated, but in other cases here are steps to port the phone number. Download and install App, send email to email@example.com that you want to port your number along with email Id you used during registering in App.
Phone Number you want to port
Alternate Contact Number
Once we have all these details, we will send you a form, which you can fill, sign and send your current provider and us. Once your current provider accept request, it will take 7 days to port in to our system, You don’t have to anything between this time, everything is automatic. Your phone will go offline for 1-2 hours.
Well, You are working very hard and growing more than what you expected and thinking about expansion. You should switch to Cloud-based phone service without much stress on your pocket. Hosted PBX https://dopenpbx.com/, offer complete business phone service, Free migration from your existing provider, Configuration from scratch, almost zero involvement from your side. 24X7 support.
Send an email to firstname.lastname@example.org and provide some basic information , get a pre-populated form, just fill in and send to both your existing service provider and dOpenPBX, your number will be ported in 7 days. Your billing will start only after you start using their service.