Migration from RBR 850 to Orbi 970

Yes,

Have the 970 series and any RBS in same room and not connected to the ISP modem/ONT. You can set up the system off line from the ISP service.

You can set up the 970 series and use same SSID name and password. 

Once you get the new system setup. Turn OFF the new RBS. Place them at same locations at outgoing RBS but don't turn them ON. 

Place the new RBR near the outgoing RBR. Don't turn yet.  

Turn OFF outgoing RBS. 

Reboot the ISP modem or ONT. As the modem/ONT is rebooting, disconnect the out going RBR from the modem/ONT and connect the NEW RBR to the modem/ONT and power it ON. Keep the outgoing RBR ON for now. Disconnect any ethernet devices from the outgoing RBR and connect them to the new RBR. 

Once the ISP modem/ONT and new RBR have come to ready, can run a quick check with a wired PC to make sure you have internet access here. Front LED on the NEW RBR should be OFF. 

If all is good here, turn OFF the outgoing RBR. 

Your wifi devices should auto migrate and connect to the new RBR. 

Turn ON the new RBS at there remote locations. I recommend powering on one RBS at a time giving 30 seconds to 1 minute before turning ON the next one. 

I do this same process when I put a different system online to test. Works well.