For anybody who isn't familiar with land lines, if you pull the phone cord out of the wall before answering, you should just be able to plug the phone back into the wall and still answer it if the person who called you decides to keep waiting. They wouldn't notice the difference. It would just continue ringing for them. And if you called somebody after they went to sleep, you'd probably be prepared to wait a while. A lot of people didn't have phones in their bedrooms, so it would take them a while to answer. (Kids usually wanted phones in their bedrooms. Adults seemed to want the phone in the kitchen area.)

Conversely, my memory is that if you were to answer the call first, and then accidentally pull the cord out of the wall, the call will get disconnected. This is because answering the phone completes an electric circuit, which is how the phone company knows it's answered, and hanging up breaks that circuit, which is what would also happen if you pulled the cord out of the wall.