how to use multiple statements inside the "THEN" block of CASE statement?

Below is the code:
SET @strTempString = case @strKeyMode WHEN 'AUTO/CYCLE' THEN  @strRefID + '|' + @strRetID WHEN 'CYCLE' THEN  @strRefID + '|' + @strRetID WHEN 'COMMERCIAL' THEN  @strRefID + '|' + @strRetID WHEN 'ISNAP' THEN  set @strFName = ltrim(rtrim((Left(dbo.CleanTheStringAdv(@strFName + '  ', 2) + '  ', 2)))) '' + @strRefID + '|' + @strLName + '|' + @strFName + '|' + @strZIPorPolType < ...