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.

Q: The professor called the secretaries .

A: The secretaries called the professor .
****
Q: The senator called the athlete .

A: The athlete called the senator .
****
Q: The scientist helped the author .

A:
The author helped the scientist .
****