Setting up Scheduled Messages for Your Clients
To set up a scheduled message for your client, you start in the usual way by clicking the little email icon next to their head shot on their Client Page:
This brings up the message composing window. Clicking the "Send later..." button at the bottom of the composing window reveals the controls to choose when you’d like your message to be sent:
Viewing Future Scheduled Messages
Whenever you’ve got one or more messages that are scheduled to be sent to your client, you’ll notice the email button gains a little extra button:
Clicking this little blue clock reveals whatever messages you have scheduled that are yet to go out:

Deleting and Modifying Scheduled Messages
You can cancel out any scheduled messages here simply by clicking the trash icon. That deletes the message fully.
If you want to view (and perhaps modify) the contents of a message you’ve got scheduled, simply click the edit icon. Doing so brings up the full compose window once again, wherein you can even revise decisions to CC yourself (or not) and add to the client’s Stream (or not):

Scheduled messages that you have set to CC yourself will arrive in your inbox at the same time your client receives it.
Automating Scheduled Message Sequences