Call On and Call At : What is the difference between these two verbal phrases?
When you call on someone, you pay them a short visit. It is also possible to say Call upon, but this is considered to be rather formal.
• The student called on the ailing principals on Wednesday afternoon.
When a teacher Calls on a student in class, she wants him to answer the question.
• I don’t understand why she has to call on me all the time.
The expression Call at is normally used in relation to a place. You usually call at some place. When you call at someplace, you visit the individual at his place – it could be the office, home, etc.
• I called at his office on my way to the airport.
The expression Call at can also be used to mean Stop.
• According to the brochure, our ship will call at five ports.
COURTESY : THE HINDU - INDIA