call on/upon sb
phrasal verbwithcallverbuk/kɔːl/us
toaskformallyfor someone to do something:
call on/upon sb to do sthThey called on thecompanytoreverseitsdecision.
If you'reevercalled upon atworkto give atalk, the veryprospectof 'getting up there infrontof all thosepeople' can beintimidating.
I should now like tocallupon thefinancedirectorto take you through theresults.
tovisitsomeone,especiallytosellthem something:
Salespeoplecallonleadsandclosesalesbypitchingthefeaturesandbenefitsoftheirproduct.