It's an old movie; won at least one Academy Award in 1950 so don't feel too bad about not recognizing the title. I know it because my Dad introduced my sister and I to some very good old movies when we were kids.

Some of the gags in the story, such as the bit about one of the phone numbers on his card being the old one, come directly from the movie.

It's an excellent movie if you do ever get a chance to see it. Jimmy Stewart plays Mr. Doud, the main character, after Harvey of course.