Some destinations have a max character count for notes.  The script below will split notes that exceed that length into multiple notes. The subject of the note will be {original subject} (Part X of Y) and the description will be the first X number of characters for the first note, and the next X number of characters for the second note, etc.  The original notes will be marked with a status of Deleted so UM will not try to insert them. 

--Split giant notes into smaller notes.
DECLARE @targetLEN BIGINT = 250;

UPDATE
    __M_Common_Notes
SET
    Final_Status = 'Deleted',
    Comment  = 'Split to multiple notes'
WHERE 1=1
    AND LEN( Final_Description) > @targetLEN;
WITH splitUp AS (
    SELECT
        Id,
        Final_Parent_Type,
        Final_Parent_Id,
        Final_Date,
        Final_Subject,
        LEFT( Final_Description, @targetLEN ) notePart,
        RIGHT( Final_Description, LEN( Final_Description ) - @targetLEN ) remainingNote,
        1 partNumber
    FROM
        __M_Common_Notes
    WHERE 1=1
        AND LEN( Final_Description ) > @targetLEN

    UNION ALL

    SELECT
        Id,
        Final_Parent_Type,
        Final_Parent_Id,
        Final_Date,
        Final_Subject,
        LEFT (remainingNote, @targetLEN) notePart,
        IIF(LEN (remainingNote)<=@targetLEN, '', RIGHT (remainingNote, LEN(remainingNote) - @targetLEN)) remainingNote,
        s.partNumber + 1 partNumber
    FROM
        splitUp s
    WHERE 1=1
        AND LEN(remainingNote) >0
)

INSERT INTO __M_Common_Notes (
    Id, 
    Final_Parent_Type, 
    Final_Parent_Id, 
    Final_Date, 
    Final_Subject, 
    Final_Description,
    Final_DisplayOrder
)
SELECT
    CONCAT(Id, ' --- PART ', partNumber) Id,
    Final_Parent_Type,
    Final_Parent_Id,
    Final_Date,
    CONCAT( Final_Subject, ' (', partNumber, ' of ', COUNT(*) OVER (PARTITION BY Id), ')') Final_Subject,
    notePart,
    partNumber
FROM
    splitUp

GO