Welcome to Flyer Talk.

If you miss any segment of a multi-segment trip, the remaining segments will be cancelled.

I'm going to guess that you are looking at some kind of Hidden City ticket. That is where a flight through a connection point is cheaper than a flight originating in the connection point.

The typical scenario is that you want to fly HubAirport to Destination. You find that if you fly OtherOrigin-Hub-Destination, the ticket is cheaper. So, rather than traveling to some OtherOrigin and flying back to the Hub, you want to just start in the Hub.

Sorry, but that won't work. Search for "Hidden Cities" in this message board, and you will find huge numbers of messages on this subject.

I'll boil it down for you:

1. Hidden City pricing exists, and the airlines are well aware of that. Higher priced tickets from a hub served mainly by that airline is a large factor in their profit.
2. Attempts on the part of the passenger to skirt Hidden City restrictions are a violation of the Contract of Carriage.
3. You can get away with it if the skipped segment is the LAST segment of your trip (not the first) and you do not check baggage.
4. Finally, don't make a habit of it, such as using Hidden City to commute to a job. The airlines employ data miners who look for these kinds of patterns. Once a repetitive Hidden City violator is identified, that person could receive a scary letter on law firm stationery with the words "fraud", "settlement", "lawsuit", "forfiture" and other similar words in the text.

I am a database administrator, but not associated with an airline. I do similar kinds of data mining all the time. It's not rocket science.