Switching trade routes?

I've been looking around for the interface to do this with no luck, but:

I have a trade route set up that I want to change to a different city. How do I do this? There is an interface I see that tells me that my route has X amount of turns left (17 turns in this case). Does this mean I can't change the route until then?

Click on the Caravan or Cargo Ship and click on Cancel Automation or whatever the hell it's called. That No Symbol thingy

There's nothing on the caravan unit that I can do that changes anything that I can see except opening up the civilpedia after clicking on the portrait.

You just have to let it ride out. after several turns it will renew and you can change the destination city then. I dont know how many turns it takes, but it'll renew.

Alright, didn't realize you were locked into that route for X amount of turns.