Change Exchange calendar permissions via command line

Get a user's current calendar permissions:

Get-MailboxFolderPermission -Identity abc@example.com:\Calendar

Give another user PublishingEditor permissions:

Add-MailboxFolderPermission -Identity abc@example.com:\Calendar -User xyz@example.com -AccessRights PublishingEditor

Remove a user's permissions from the calendar:

Remove-MailboxFolderPermission -Identity abc@example.com:\Calendar -User xyz@example.com