Lowering price for the current students

I lowered my price to gain more students and am waiting for the approval, but I don't know when to change the price for my current students.

They have recurring weekly lessons with me. Should I wait until their subscription expires and they have no scheduled lessons? I see reserved spots for one of my students at a certain time in the future. I know how to change the price for the current students, but don't know how it affects them.

I just want to be honest with them and have the same good deal as the future students. How do I help them?