Teacher:In this task, you are given a premise sentence. Your task is to write a new sentence by substituting the subject and object (i.e., the input's subject should be output's object and vice versa.). The generated sentence must be fluent and shouldn't change the voice (i.e., passive or active) of the input.
Teacher: Now, understand the problem? Solve this instance: The doctors by the actor called the president .
Student:
The president called the doctors .