Originally Posted by
jsloan
Every fare is different, so I can decipher it for you, but I'm not sure it helps. That particular fare does not allow stopovers (STOPOVERS NONE), which means that it wouldn't be able to be used if you extend your stay in DC beyond 24 hours. Your ticket would have to be re-fared, either to a different P fare that allowed stopovers, a Z or higher fare that allowed stopovers, or to a combinable set of BRU-WAS+WAS-EWR fares.
Permitting stopovers in the US is, as far as I'm aware, extremely unusual. If you wanted to use the residual on the ticket it would refare to ZRH-WAS (or BRU-WAS in the second example) using the fare table in effect at purchase and the properties of the new journey, and assuming inventory was available in your cabin at your current rbd and all higher codes, but no lower codes.