Getting each status change in a table
This type of requirement comes under the banner of "gaps and islands". A popular approach is

WITH T
     AS (SELECT *,
                DENSE_RANK() OVER (PARTITION BY ItemId ORDER BY DateOfChange) - 
                DENSE_RANK() OVER (PARTITION BY ItemId, Status ORDER BY DateOfChange) AS Grp
         FROM   ItemTable)
SELECT ItemId,
       Status,
       MIN(DateOfChange) AS Start,
       MAX(DateOfChange) AS Finish
FROM   T
GROUP  BY ItemId,
          Status,
          Grp
ORDER  BY Start