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 presidents contacted the student near the doctors .
The doctors contacted the presidents .

The president thanked the lawyer .
The lawyer thanked the president .

The student called the authors .

The authors called the student .