Change contraint in a table description

Hello,

When doing a description of a table I get the following line:

Check constraints: "check_auth_method" (((((method = 'NONE'::character
varying) OR (method = 'IMAP'::character varying)) OR (method =
'POP'::character varying)) OR (method = 'FTP'::character varying)) OR
(method = 'LDAP'::character varying))

I need to modify this line to add RADIUS as a constraint. How do I get to
where I can modify this line? Is it a simple "SET CONTRAINT" SQL command or
do I have to go to this "check_auth_method" (where ever that is)?

Quinton Williams
Telecommunications Analyst
University of Houston
(832) 842-4680