The OP constructed a ticket with a spurious tiny segment at the end in order to trick an online travel agent's system into not charging a Carrier Surcharge, A.K.A "Fuel Dumping". Even if the OP could get an agent who was empowered and capable to make the changes, any agent worth their salt is going to spot this immediately and ensure the OP is charged the full extent of any fare change and fees involved.
OP, the chance of you getting what you want here is approximately 0.002%. Either fly what you booked, or forfeit the rest of the trip, it just isn't worth the effort trying. Expedia won't want to touch it with a barge pole, Comair won't want to get involved with a VS ticket, and VS will be less than impressed at not getting their YR/YQ.