When the change is from a single-byte to a multibyte character set:
isql -Uuser_name -Ppassword -Srssd_name -Jeucjis < $SYBASE/$SYBASE_REP/scripts/rsspmsg2.sql
When the change is from a multibyte to a single-byte character set:
isql -Uuser_name -Ppassword -Srssd_name -Jiso_1 < $SYBASE/$SYBASE_REP/scripts/rsspmsg1.sql