Like the above stated I would put live rock and corals and the fish in buckets wit the current take water.
I would save as much water as you can so your not going to have another cycle.
Drain the tank as much as you can and then get to shoveling out the coral...when the majority of it is out you could attempt to tip the tank and use a hose to wash the rest out.
Then when the tank is set back up. Put the lr
in and sand. I would mix some sw
up to make up the diff you lose the night before and put a heater. Try to match the salinity an temp of your tank.
Then I would add the new sw
with the old...let it mix for a little bit then acclimate the livestock....
That's my best guess