ph.

1. 要求;呼吁;号召
If you call on someone to do something or call upon them to do it, you say publicly that you want them to do it.

2. (短暂)拜访,探访，看望
If you call on someone or call upon someone, you pay them a short visit.

1. have recourse to or make an appeal or request for help or information to

e.g. She called on her Representative to help her
She turned to her relatives for help

Synonym: turn