call on

fe’l verb

1. To visit (a person); to pay a call to. I really should call on my aunt more often.
2. To select (a student in a classroom, etc.) to provide an answer. He sat there, baffled, hoping nobody would call on him.
3. (also call upon) To request or ask something of (a person); to select for a task. The king called on his subjects to take up arms and defend the kingdom.
4. (also call upon) To have recourse to. Exhausted, he called on his last ounce of strength.