[randy500]

Sand it in an X and probably do it wet since the epoxy stays soft for a long time. I would try to scratch most of the run off using a new razor blade held perpendicular to the panel, scape it quickly back and forth the scratch the run off, continue scratching on the run until flat. If you don't do that before sanding you will usually be left with a bit of a run that is now just hard to see and feel. Make quick work of the run.
You can do the same with final finish whether single stage or base clear too, prior to sanding and buffing.