Hi Swetz,
You can make two groups. Let one group be observers and the other group act as performers.
Performers: Give them some role play according to what you would like them to learn. For example, in telephone etiquette, one essential aspect is to be polite. Provide role-plays such as 3-4 people approaching another person for different tasks simultaneously.
Observers: Allow them to observe the performers and identify the advantages or disadvantages of their actions.
There can be various exercises on ice-breakers related to this topic. What I have written is just a general overview.
You may find many articles on ice-breakers on cite hr. Just type "ice-breaker" in the search query, and hopefully, you will find what you are looking for.
Regards,
Anuradha