You will be given a definition of a task first, then some input of the task.
In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

Shills publicly help or give credibility to a person or organization with which they have a private relationship .
Output:
A shill , also called a plant or a stooge , is a person who publicly helps or gives credibility to a person or organization without disclosing that they have a close relationship with the person or organization .