He called on me a while back and asked for my support.

He called on the outside world to try to understand the situation.

He didn't really have to call on the old man.

I do hope you will call on me again soon.

At five he would call on the new president of the college.

But he called on the industry to police itself in other areas.

When he calls his daughter on the phone, what do they talk about?

Someone came to ask if I would not call on her at least once more.

In your hour of need, you may call on me.

He called some friends of his on the police force.