SELECT T1.Name FROM editor AS T1 JOIN journal_committee AS T2 ON T1.Editor_ID  =  T2.Editor_ID GROUP BY T1.Name HAVING COUNT(*)  >=  2
Show the names of editors that are on at least two journal committees.
[Schema (values) (types)]: | journal_committee |  journal : journal_id (text) , date (number) , theme (text) , sales (text) | editor : editor_id (text) , name (number) , age (text) | journal_committee : editor_id (text) , journal_id (number) , work_type (text);