No, but you can cheat:
DECLARE @X TINYINT = 0
;WITH SampleTable AS (
SELECT SOMECOLUMNS = 'SOMECOLUMNS', COLUMN1 = 'COLUMN1', COLUMN2 = 'COLUMN2', COLUMN3 = 'COLUMN3',
COLUMN4 = 'COLUMN4', COLUMN5 = 'COLUMN5', COLUMN6 = 'COLUMN6'
)
SELECT SOMECOLUMNS, x.*
FROM SampleTable
CROSS APPLY (
SELECT COLUMN1 = 'COLUMN1', COLUMN2 = 'COLUMN2', COLUMN3 = 'COLUMN3' WHERE @X = 1
UNION ALL
SELECT COLUMN4, COLUMN5, COLUMN6 WHERE @X <> 1
) x
For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden