Rename constraint?

I have tables which were created with unnamed constraints:

# \d <table>
...

Check constraints: "bad_job_time" fn_validate_cron(job_time)
                   "$3" (arguments <> ''::text)
                   "$2" (job_time <> ''::text)
                   "periodic_jobs_job_length_bad" (job_length > 0)

How can I identify and rename the "$2" and "$3" constraints?

--
Jeff Boes                                      vox 269.226.9550 ext 24
Database Engineer                                     fax 269.349.9076
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