Curve...

Every initial curve you selected for your AgencyGP will have a proxy that appears in this list. It may not have the same name, but you can tell which curve it is because when you select it, the curve's image on the base plane should highligh.

You can edit the design one starting curve at a time. Select a shape from this list and expand its contents. You will see "Parameters" and "Commands". These are the two sets of values that determine how a shape will be taken from an initial curve and modified into an extruded shape. You are free to modify either.

Note that because of interactions between curves, you may not see a given curve in a Maya scene at all. It may be intersecting with another curve, and serving only to slice away from that one. Just play with the values and you should be able soon to tell what is going on with any shape in your scene.