I've done this....
If you dont have much in terms of fish or coral, you can set up a temp holding tank. Rubbermaind tote, small glass tank or brute trash can works well for this, or Whatever is of decent size and holds water. Doesnt have to be huge fish and coral will be fine in tight quarters for a short time.
Get some extra rubbermaid storage bins/totes.
Make up lots of fresh salt water.
Before moving or doing anything pump water from main tank into temporary holding tank, and the totes.
Setup the temporary holding tank with a powerhead, and a heater. No other equipment is necessary.
Remove corals one by one while you can still see in the tank to holding tank.
Then pull rocks and swish them in your tank to get crud off them. Can brush off algae and reswish in main tank as needed. Move a few pieces of rock to temporary holding tank for the fish and coral and the rest to the rubbermaid totes.
Once all the rock is out you can pump water out and work on catching fish. gets easier as water level gets lower.
And once the tank is empty you can scoop out all the sand with a cup into a 5g bucket. You can for sure reuse the sand if you have the patience. Fill a bucket halfway with sand. Bring it outside and use your hose and wash away. Will take 30mins to an hour per half a bucket of sand. Wash and stir the sand til water comes out clean, may seem like it never will but it eventually does. Then drain off as much water as you can. Dont worry about residual tap water. It's so minute it wont effect anything.
You can now go about moving and resetting up the tank.
Nows a great time to take your time and get your rock scape exactly how you want it.
You can use your fresh rinsed sand or new sand, and all fresh saltwater. As long as your rock stayed wet in the bins there will be minimal to no die off.
You can let the tank run a few days and use a test kit to monitor ammonia and nitrite to make sure you don't get a mini cycle, if you do it will be very short lived.
Fish and coral can go back to the tank whenever you feel confident that theres no ammonia or nitrite. Fish will be fine in the temp holding tank as long as theres water movement and temp stays consistent. If it will be a few days and tank is small top off water will be necessary.
Good luck!