Yes, it was possible--All these cell phone switches are just computers.
and in the past I was talking to a very friendly c/s guy when doing an
esn change--he volunteered, I could just keep both phones on--I was
already aware it was possible, but inquired, was informed it was always
there, I got him to tell me where to find it on the  computer for future
reference, and got his ext no--for two or three years, worked--but in
the latter part of it the caller id function failed to work--finally on
a latter esn update, they refused to carry it forward.  there is also
cloning which was done thru about 1998, was made illegal to do--but I
still see it advertised--however, even with the cloning being preformed
on a phone( and the ads show the clonable phones to be rather old) most
carriers have ways to block it from working--this is all I know--would
like to hear more if available.

"Sharpie" <NOMAIL@NOMAIL.NOMAIL> wrote in article
<z0Q2b.55974$Sq.9534732@twister.nyc.rr.com>:

Here's something that you could try.... It is easy to switch between two
phones on the Verizon web site.  If you know you will need analog, just
switch to your backup phone.  I tried it out the other day, and the second
phone was working almost immediately.  I switched from my Samsung a530 to my
old Samsung 850 and then back again.  Nice new feature!

Bill