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 artists called the tourists near the doctor .
The tourists called the artists .

The scientists helped the doctors in front of the authors .
The doctors helped the authors .

The students mentioned the doctors behind the scientist .

The doctors mentioned the students .