Sort of. I've been wondering the same thing. One option -- probably not what you're hoping for -- is that your workout data will sync to any number of partner sites (e.g., mapmyrun), which then allow you to go in and override the values automatically sent by the Band. An even uglier option is to export the workout data (Unband app works well) and fiddle with the values in the GPX file. Those too can then be uploaded to a partner site. However, once you press "End" there's no option to alter them in the Health app or on the Health Dashboard. :angry:
I don't remember if this is somewhere in the stickied post for feature suggestions, but I'd really love to see a trim/join function for workouts, so like you're wondering, users could fix errors that occur (e.g., you pause in the middle of a workout and it accidentally ends the run).
-Matt