INSERT INTO GameSchedule(StartTime,EndTime, GameType)

select NewStartTime,NewEndTime,GameType
from
(
	SELECT 
	DATEADD(dd, 1, StartTime) AS NewStartTime, 
	DATEADD(dd, 1, EndTime) AS NewEndTime, 
	GameType,
	ROW_NUMBER() OVER (order by GameID DESC) as rnum
	FROM GameSchedule AS GameSchedule_1
)dt
where rnum <= 16
order by rnum DESC

;WITH cteSource(GameID, StartTime, EndTime, GameType)
AS (
	SELECT TOP(16)	GameID,
			DATEADD(DAY, 1, StartTime) AS StartTime,
			DATEADD(DAY, 1, EndTime) AS EndTime,
			GameType
	FROM		dbo.GameSchedule
	ORDER BY	GameID DESC
)
INSERT		dbo.GameSchedule
		(
			StartTime,
			EndTime,
			GameType
		)
SELECT		StartTime,
		EndTime,
		GameType
FROM		cteSource
ORDER BY	GameID