I was helping a co-worker set up a new to her Tello this morning in the office.

She was up and flying and then mid-flight, lost Wifi connection to the drone.  I think it was due to interference as it occurred directly under a wifi antenna for the office building.

At that point the drone just hovered, and she had no control.

We tried going into her phone settings and reconnecting to thre Tello wifi, which then showed as being connected, but in the Tello app, there was still no connection.

After a couple minutes of fiddling with the phone and Tello app trying to regain connection, I finally, carefully, caught the hovering drone and powered it off.

My question is... what is a person *supposed* to do in this circumstance to regain control of the drone?  What if it happened to be hovering 10 feet off the ground, I wouldn't have been able to catch it.

Dear customer,
If the mobile device’s remote control signal is lost for more than 50 seconds, signal strength is poor, or the Tello has been exited, the aircraft will trigger failsafe protection, then descend and hover at 30 cm. When the aircraft runs out of battery, it will land.
In respect to the scene of hovering you mentioned, based on the description of flight environment,  it is probably caused by signal lost, please select an environment far away from electro-magnetic interference, such as Wi-Fi hotspots, routers, Bluetooth devices, high voltage lines, high voltage power transmission stations, mobile base stations, or broadcasting towers.

As for the problem of reconnection, it might be caused by APP crush, plesae log out Tello APP and log in again.

Please read the manuals on RYZE official website to know more information about the drone and flight environment requirements.
https://www.ryzerobotics.com/tello/downloads

Hope my reply could help you.