A:Answer Lively/Jitterbug is its own cellular service, which they "lease" or contract out to Verizon. Data, Voice, and Text messaging is billed by Lively. Without being a hacker or whatever (which probably goes against their TOS), these phones do not support any other network.
In addition to the data,voice,texting, they have other services including GPS tracking, a concierge type operator service, and app-less Lyft where you call the operator and they make arrangements. There is more.