changing flower times

Indoor, 2, 4ft, 3rd week flowering positive females.
I want to change my light and dark hours by 12.
Basically flip from 7am/7pm to 7pm/7am.

Any Adverse reactions?

Thanks for any and all input.

SidNastyVicious

should be fine but don't do it often or it will stress em out

Yes NP I changed my flower time by 12 hrs before weeks into flowering, I suggest a long night.