I did that twice.
Normally I will off the return pump and let the wavemakers take care for a week or two
while I do the transfer.
I will siphon about 60- 70 % of the sump water to the new tank.Then I will clean the return pump
,skimmer,denitrator and FR.
Then I set up the above cleanup equipments.
Next I will transfer about 20% of the main tank water and transfer all corals to the blue tub .
Now I will slowly transfer the LR to the new tank and add in enough newly mix salt water to cover the
live rocks.
This usually take a day or 2.
When all LR is transfer I will siphon the old tank water to the new tank after all the dust settle down.
I let the new setup tank cycle for 1 day and take reading of all the common parameters.
If everything is ok I will start the transfer all the corals from the blue tub to the main tank.
This is follow by very close monitoring of all the corals reaction to the new setup
Hope that help