Late period on calendar...

Emily • 27, married to my high school sweetheart. One daughter, 9/12/13. One angel baby, 8/11/15.
Is there a way to let your calendar know that your period is late? I know how to change the start date, but how is there a way to mark missed days? I'm sure there is another question about this or it is located in "Help"...but I couldn't find it anywhere. Thanks!