Some help on changing light cycle

Hello people!

Currently I got my seedlings under fluorescent under 18 hours of light starting at 7am.

I recently finished my growbox and realised that for security reasons (mainly noise) I have to flip the light cycle to start at 1 am.

Btw as soon as I move them I'm using the 600w mh if that makes any difference.

So what's the right way to alter the schedule?

Any help would be greatly appreciated
Cheers!

Just to clarify I'm talking about autos.

Set the timers back or forward an hour a day until it's the time you need them to go off and on...

i would just flip them to whatever you need them at .... as long as there is enough light it doesnt matter