Switching lights

I 'm sure this has been posted b4,but i can't seem to find what i'm looking for, so bear with me.I'm running a 400hps durning the day time and the temp is just getting way to hot, 95F. At night the temp drops to about 75(dark period).I've been flowering for 10days, on at 8am, off at 8pm and i need to change it to on at 8pm off at 8am.What the least stressfull way to go about this?should I keep it dark for 24hrs, then resume day time at night?sorry if this is a redundant thread.

imo i would give it the 24 hour dark period then resume with your 12/12. i run mine at night also due to the summer time heat.