How to give access of inbox to booking staff members?

Question:
I want to give access to chat/inbox to booking staff members. I checked the roles and permissions settings but no luck. Is it possible to change the permissions?

What are you trying to achieve:
I want our trainers to have the flexibility to talk to their clients, however, the have the flexibility to call them but as a business, we would prefer the communication to be done through the chat message.

What have you already tried:
I have checked the roles & permissions settings but didn’t find any related permissions there.