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.

The president behind the lawyers thanked the actor .
The actor thanked the lawyers .

The senator helped the actor who recognized the judge .
The judge helped the senator .

The doctor thanked the secretaries .

The secretaries thanked the doctor .