meaning of "exerts influence"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hi All,

I want to ask a department leader to persuade/force his employee to reduce his mailbox size because it’s over the limit.

I want to use the word influence

Please influence the user to reduce its mailbox size

Please exercise an influence on the user to reduce its mailbox size

Please exerts influence on the user to reduce its mailbox size

2

.
Difficult to do without sounding too demanding. Perhaps something like ‘Could you try to exert your influence over Mr X and ask him to reduce his mailbox size?’
.