call on/upon sb
phrasal verb with call verb uk/kɔːl/ us
to ask formally for someone to do something:
call on/upon sb to do sth They called on the company to reverse its decision.
If you're ever called upon at work to give a talk, the very prospect of 'getting up there in front of all those people' can be intimidating.
I should now like to call upon the finance director to take you through the results.
to visit someone, especially to sell them something:
Salespeople call on leads and close sales by pitching the features and benefits of their product.