prevail on/upon somebody phrasal verb formal (see also prevail)
to persuade someone
prevail on/upon somebody to do something
She prevailed upon her father to say nothing.

[TahlilGaran] Dictionary of Contemporary English ▲

prevail upon
to ask or beg someone (for a favor)
I had to prevail upon my friend to lend me some money for my holiday.

[TahlilGaran] English Idioms Dictionary ▲

prevail upon
v. To bring to an act or belief; cause a change in; persuade.
He prevailed upon the musician to entertain instead of the absent speaker.
He prevailed upon me to believe in his innocence.

[TahlilGaran] English Idioms Dictionary ▲

prevail upon someone
to ask or beg someone (for a favor)
I had to prevail upon my friend to lend me some money for my holiday.

[TahlilGaran] English Idioms Dictionary ▲