As your project progresses, task start and finish dates may slip, resource assignments may change, and so on. To inform team members of these changes, send them TeamUpdate messages. When team members are informed of schedule changes, they can alert you about how those changes affect them, thus helping you avoid potential schedule problems.
You can send a TeamUpdate message only to a resource assigned to a task. If you remove a resource from a task, you won’t be able to send that resource a TeamUpdate message.
To send a TeamUpdate message