call on

verb5

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. •
   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. •
   To have recourse to.

   • Exhausted, he called on his last ounce of strength.
   • The young adventurer set out on the new planet alone, thankful that she could still call on her captain for advice in case of emergency.
5. •
   To correct; to point out an error or untruth.

   • The salesman persisted in quoting a rate higher than was listed, until we called him on it.