Is there any way to change lights inside an entity in game?

[FlawlessHappiness]

No, I don't think it's possible
You cannot use a script to go inside an entity and edit something in there.

Picture this:
The light in the entity is probably called "PointLight_1".
You probably also have a pointlight in your map called "PointLight_1".

You probably also already know that you cannot have to entities with the same name. Therefore it would be impossible.

VVV LOOK HERE VVV

Though, now when i think about it. When you AddPropForce to the doors of a cabinet you write the names like: "cabinet_doorLeft", because that's the name of the cabinet_+the name of the door in the cabinet.

What if you used fadelightto and then called the light this:
(In this example the entity is called "entity")
"entity_PointLight_1"

Try it. Maybe it works.