Unfortunately CCs don't have a built-in change event. You can create custom change events however they can be intimidating and unwieldy:
http://gregmaxey.com/word_tip_pages/...om_events.html
About the best you can do is employ the built-in On_Exit event where the event occurs when the user checks then tabs or clicks to the next control.
What is the range identifier of your "next line?" Is it another titled content control?