Darken windows in the background

There are two windows in the background of the frame. The upper parts are too bright. Can you darken those parts, as if it were in the middle of the night?

There is also a slightly transparent window curtain in front of it. The hard part is to make it look as natural as possible.

The level of darkness can be referenced from the downer part of the windows, which is almost black.

If you apply, please send us an example of how it could look like.

Thank you in advance!