Need AT&T ROM for Razer Phone 2

Nope.  that would be completely pointless since AT&T reneged and never gave their version of the razor to Wi-Fi calling either.
Rooting is  not a discussion that can appear here.  

Thanks for the reply. There was no rooting involved nor was it mentioned. I found what I was looking for and the wifi calling is now working.

Does it really?  Turn airplane mode on, then WiFi back on.  Then place a call.  Post a screen shot.  

I'm not sure if you are aware of this but you don't need to be in airplane mode to make a wifi call.

I think the idea was, as a test, to shut all radios off first, then just turn on wi-fi by itself.  Eliminating the possibility that cellular was still being used.

@Cindy-wfwe   As @joeldf  wrote, unless you put it in airplane mode, then turn WiFi back on, there is no evidence it works.  Your screen show no notifications to that effect.  
I could enable on my oneplus, and my sons Razer, but it did not work.

You asked for a screenshot. I gave you one. As for your Son's phone that's not my concern. I am getting the impression that you think I'm lying and I don't appreciate that. You have no idea how I got it to work and it is WAY above your head. I could explain how I achieved such a feet but you wouldn't understand it. All I care about is that I am now getting crisp and clear calling. That was my goal and have achieved it.

*****

[Please keep it courteous]

@lizdance40 , actually the screen shot has the status line, but the icons are black against a really dark gray background.  The phone active icon is in the upper left along with some  microphone icon. On the right is the alarm clock, the wi-fi symbol, the airplane mode symbol, then the battery symbol and percentage.  No carrier strength icon.

Seems legit to me.

@Cindy-wfwe   No need to be rude.  I use an iPad, not a desk or lap top. It does not show the notification bar in your photo.  If you were able to use Wifi calling in airplane mode, great.  It has failed to work for many customers, and AT&T removed Wifi calling from its specs online.