Article Links which already shared in reply http://www.aspforums.net/Threads/171151/How-to-update-table-after-24-hous/Replies/1#Replies for Automated Email Notification Please refer that. You just need to create the New Job as per step explained in the article link. As per your requirement you just need to make change in Job from SqlCommand type to Sets its Schedule Time.
If you need to check the Status column whose value is reserve from the table which you want to delete if it not confirm after passing 24 hour then you need to check datedifrrence of DateTime column by using DateDiff function of sql also need to check the status is Reserve if its reserve and time passed as more than equal to 24 hour then you can delete it.
Below is sample SqlCommandQuery to check the datediffrence more than equal to 24 hr also check status column whose values is Reserve.
DELETE FROM TableName
WHERE DATEDIFF(HH,YourCompareDateColumnName,GETDATE()) >= 24
AND UPPER(StatusColumnName) = 'RESERVE'
Just create Job and schedule its Time as per you requirement.
