Search for a person and use MS Team to connect
Search for your colleague and then use Microsoft Teams to connect with them via video call, phone call, or messaging.
Learn how to set up the Chat Integration, refer to Set up the Chat Integration.
Follow the Steps
From the Concierge menu, tap on Maps to begin.
The menu items in the Concierge menu are configurable so the menu item could be called Find & Book or another name that suits your business, see Set up the Concierge Menu for 3 or more menu items.
In the Find people, spaces, and more field, enter the name of the person.
As you type in person's name the list is filtered.
Tap on the name of the person.
The person's details displays.
Tap the Microsoft Teams 
icon.
The Microsoft Teams app displays.
You can either start a video call, phone call, chat, or leave a voice message.
Video Call
Start a video call ... tap the Video
icon.
Phone Call
Start a phone call ... tap the Phone
icon.
Chat
Send a chat message
Voice Message
Leave a voice message .. hold down the Voice 
icon, record you message, and when you have finished recording release the icon.
The voice message will display ready to be sent off.
Tap the Send
icon and your voice message will be sent.