Scenario:

You’ve added too much milk to your macaroni and cheese and now it’s liquidy.

Solution:

You can turn the burner on the stove back on and bring the macaroni and cheese to a boil. Boil the milk down to the desired level. You will want to be sure to constantly stir the contents to make sure that non of the milk (or cheese sauce if you’ve added it in) burns on the bottom of your pot.