Try this,

should work with any duplicate comma separated endings

UPDATE 

  table

SET 

  Location=LEFT (Location, LEN(RTRIM(Location)) - CHARINDEX(',', REVERSE(RTRIM(Location))))

WHERE

  CHARINDEX(

 SUBSTRING(

  RTRIM(Location),

  LEN(LEFT (Location, LEN(rtrim(Location)) - CHARINDEX(',', REVERSE(RTRIM(Location)))))+1,

        CHARINDEX(',', REVERSE(RTRIM(Location)))),

 LEFT(Location,LEN(RTRIM(Location)) - CHARINDEX(',', REVERSE(RTRIM(Location))))

   )>0

Magnus W