Select an OrderID always before the current passing OrderID:

select an OrderID before the OrderID you are passing. check the below scenario for more clarification.

 ;WITH CTE AS 

(

  SELECT

    rownum = ROW_NUMBER() OVER (ORDER BY orderID),orderID FROM Orders

) 

SELECT 

  cur.orderID as CurrentID , prev.orderID as PrevID

 FROM CTE cur

INNER JOIN CTE prev on prev.rownum = cur.rownum - 1

where cur.orderID=27 or cur.orderID=29

OUTPUT: