Got a couple of questions to ask about regarding to English grammar.

How do you teache 'passive voice'?

Example:
Active: My mom calls me "Honey!" (I have no idea why the hell this is an example...)
Passive: The jungle is also called the 'rain forest'.
The office is cleaned everyday.

I understood the meaning of 'passive voice', but can anyone give suggestions of how to teach them in an ESL class?

Many thanks.