This forum here has really helped me a lot with certain problems and I got one more question to u pros out there

So I have my characters, backgrounds, dialogue, etc. all ready and finished. The basic scene is a living room at broad daylight (you can see the sun shining outside the window) with 2 characters talking to each other. For my main joke I have one of my charcaters say something like: "Last night something strange happened" and then I want to make a cut to the same room, but only at night time, so I need everything a little darker. What is the best way to accomplish something like that?
Thx for your help!
sys