OK. Looks to me like you're pretty new to SQL. So, can I suggest that you take some time out to ensure you understand how both examples work?

;WITH cte ( requestid, approvallist, approvelevelname, length )

AS (SELECT requestid,

CAST('' AS VARCHAR(8000)),

CAST('' AS VARCHAR(8000)),

0

FROM dbo.ts_status

GROUP BY requestid

UNION ALL

SELECT p.requestid,

CAST(approvallist + CASE

WHEN length = 0 THEN ''

ELSE ', '

END + p.approvelevelname AS VARCHAR(8000)),

CAST(p.approvelevelname AS VARCHAR(8000)),

length + 1

FROM cte c

INNER JOIN dbo.ts_status p

ON c.requestid = p.requestid

WHERE p.approvelevelname > c.approvelevelname)

SELECT requestid,

approvallist

FROM (SELECT requestid,

approvallist,

Rank() OVER ( PARTITION BY requestid ORDER BY length DESC )

FROM cte) d ( requestid, approvallist, rank )

WHERE rank = 1