Need advice for changing light schedule

I need to move the light schedule in my flower room back 3 hours so that I can get in and give them enough attention each day. I'm going to have a week with minimal plants in there soon so that will be the time to do it but I'll still want to keep the few in there in good health.

I was thinking of cutting an hour of light at the end of the day and then giving the regular 12 hours of dark (making it an 11/12 for a day). Then leaving on 12/12 for a couple days and doing it again.

Would this be the way to go? Should I just do 11/12 days for 3 days in a row and then go back to 12/12? What would be the least stressful for the plants?

Just change them...unless you play with timings often, this change won't affect them.
FF

I'd just go ahead and change they will be absolutely fine, I've altered the timer countless times to suit my hours.

Just changed mine and they didn’t miss a beat

Change the timer to the schedule you want and forget about it.