I assume you're asking about the passive causative form. This is used when Person A does not do something for himself/herself—instead, Person B does it for Person A. We show the difference by adding "had" or "got" in the past tense, and "will have" or "will get" in the future tense. Examples: Luis changed the oil in his car (This means Luis did the work) Luis had the oil changed in his car (This means someone else did the work for Luis) Miranda will cut her hair tomorrow (This means Miranda will hold the scissors) Miranda will get her hair cut tomorrow (This means Miranda will go to the salon and someone else will hold the scissors and cut Miranda's hair)