Switching back to vegitative please help!!

I have 46 plants and went flowring 12 days ago
I already discovered 9 males and about 15 females

I have to switch back to 18 to 24 hours due to a major issue
they have been under 20 hours under 250w of cfl for 1 month and another on just 250w hps dual spectrum in just 5 liter containers in soil with fertilizer

is it gonna stress the plants hard enough to kill them
if not how can i try best to be as safe as possible?

It won't likely kill them. May stress them a bit but they should be okay. It will take them a few weeks to get used to the light change and revert back to veg though.
Just to be clear though, what light cycle did you have them on and what cycle do you plan on changing to?

I've read it takes 2 weeks for them to revert back to veg. But I'm just a noob so I have no experience with doing that on my own

you can reveg no problem

It'll be ok.

It was 20/4 then to 12/12
I'm changing it back to how it was 20 hours/day

So you sexed them, plan to reveg them and pop em into flower?

As long as they fully reveg before going back into flower I see no problems.

I know a few outdoor growers do that with no problems - start them at 12/12, sex them, then outside they go.