Update statement with subquery

Hello:
Can someone assist me with this, please.
I'm getting subquery returned more than 1 value from the code below. I realize that Documentrecords_62 table will bring back multible rows and that's expected. For each row I need to do a carriage return, that's why I'm using CHAR(13) and CHAR(10).

UPDATE Documentrecords_90
       SET Change_Descriptions =
              (SELECT
                  CAST(ChangeNumber As  varchar(5)) + '     ' + 'WAS: ' +
                  CAST(TextBefore) As  varchar(100)) + '     ' + 'CHANGED TO: ' +
       &nb ...