Yes, there is a "way", but it takes a little bit of data manipulation.
Currently "Corral" info gets thrown into the "Announcer Notes" field when you sync with RunSignUp.
So you could pull everyone down from RunSignUp, export all participant info to CSV file, drag the "Announcer Notes" column over onto the "Athlete Type" column, and then re-import the file. If the only change the participant data is the new "Athlete type" then of course all other info stays the same and only the Athlete Type is updated.