Converting User mailbox to Shared or Room mailbox

1. Open Exchange Management Shell
2. Enter the following command: get-mailbox -identity <username or display name> | set-mailbox -type shared 
3. Afer the process completes, the mailbox will show as a share box.

Example:

***To convert shared to a user mailbox enter the following command:

1. Enter the following command: get-mailbox -identity <username or display name> | set-mailbox -type regular 

Convert mailbox to Room type: 

1. Enter the following command: get-mailbox -identity <username or display name> | set-mailbox -type room