When it's really wet and then gets down in the 20s F, my heat pumps will go into defrost mode.
The heating mode switches to cooling mode, but the indoor air handler fan will be off or very low. So as not to cool off the house.
That works really well when the ice isn't too thick..
So sometimes, when there is a lot of ice on my main house unit, and I want get rid of the ice faster. I'll change to mode to Cool the house! The living room gets pretty cool, (we wait in the den, where it's warmer). After 10 or 15 mintues, I turn if off, and wait for more melting.
Many times, I'll watch the ice on a security cam located in back of the outdoor unit.
I leave the unit off until the ice is pretty much gone off the warm HX coils, and return it to heating mode (66 or 67F) and go to bed..