We can transfer or "port" your existing number or numbers to us. A a single line number can be changed to a multi line number. So, for example, a single number on a single line can support one call, whereas once it has been ported to VoIP, it can allow multiple calls at the same time (as much as your internet connection can handle). should you move office you can still keep your numbers doing this means you won't lose any existing advertised numbers you have.