Remove Duplicated row on a iseries table

I have a table similar to belowCustomer Referencedate card_number created_by John 112233451 2008-02-01 48001796 SenJohn 112233451 2008-02-01 48001796 SenEddy 123565654 2008-03-26 48001799 MarkMary 124578128 2009-10-27 48001850 MarkFrom the above table I need to remove all duplicated rows leaving one row of each record on the table.i.e I need to have one record of customer ‘John’ on the table. The duplicated rows having same values on all columns and thus difficult to use max or min.Thanks