Uhhhhh…. no. 6922 swap-in would be a bad thing (heh heh).
They prefer different heater voltages (i think(?)).

But as noted, any 12a**-style tube can be successfully swapped in for slightly less gain, and a little more clean headroom.

There’s a chart at “tubestore” showing relative gain of these tubes, here:

http://thetubestore.com/gainfactor.html

Or you can try a 12dw7… instead of both triodes being identical, the first stage is a 12ax7 (gain of prox 100), the second stage is a 12au7 (gain approx 20), so it’s roughly the same gain as an at7, but i thought it responded differently. A little more… “airy” if that makes sense. ‘Course it could be all psychological (I drink a lot).

Good luck!