You'd probably end up with a 3d printed version of the person calling you.
As far as I can gather the printers software does not use up too much computing power.
The raspberry pi can control a printer so I'd imagine the app would probably just keep running
In the background until you've finished your call. You'd probably have to use an SD card on the printer for the gcode
And then use the phone to run the code and keep an eye on temps.