SQL Convert UK to US date format

Please help.  I have the below query and I want to get the dates to use US format MM/DD/YYYY to run a report using Crystal Reports.  I am using the following line of sql:-

      where CONVERT(DATETIME,(substring(A_AUMDTETME, 7, 2) + '/' + substring(A_AUMDTETME, 5, 2) + '/' + left(A_AUMDTETME, 4)),103) BETWEEN {?1StartDate} AND {?EndDate}


The entire sql query is listed below:-

DECLARE @today VARCHAR(50)
DECLARE @previousDate VARCHAR(50), @todayDate VARCHAR(17)

SET @today = (SELECT DATENAME(WEEKDAY, GETUTCDATE()))
SET @todayDate = dbo.CTUTCDate()
SET @previousDate =
CASE
      WHEN @today = 'Monday' THEN
            (SELECT CONVERT(VARCHAR, DATEADD(DAY, -3, GETUTCDATE()), 103))
      ELSE
            (SELECT CONVERT(VARCHAR, DATEADD(DAY, -1, GETUTCDATE()), 103))
END

SELECT
      Table1.[Instrument],
      Table1.[YtD P&L Value]
FROM
(
      SELECT TOP 200
            ISNULL(I.A_TKRCDE, I.A_INSNAM) AS 'Instrument',
            ROUND(SUM(A_ACCDAYPNLVAL), 2) AS 'YtD P&L Value'
      FROM T_ACC_AUMDET AD
      LEFT JOIN T_ATH_INS I ON AD.A_INSID = I.A_INSID
      LEFT JOIN T_ATH_INSTPEMAP ITM ON I.A_INSCLSCDE1 = ITM.A_INSCLSCDE
      WHERE A_AUMID IN
      (
            SELECT A_AUMID
            FROM T_ACC_AUM
      where CONVERT(DATETIME,(substring(A_AUMDTETME, 7, 2) + '/' + substring(A_AUMDTETME, 5, 2) + '/' + left(A_AUMDTETME, 4)),103) BETWEEN {?1StartDate} AND {?EndDate}
            AND A_ACCID = '{?AccountName}'
      )
      --AND ITM.A_INSTPECDE <> 4
      GROUP BY I.A_TKRCDE, I.A_INSNAM
      HAVING ROUND(SUM(A_ACCDAYPNLVAL), 2) <> 0
      --AND ROUND(SUM(A_ACCDAYPNLVAL), 2) < -500000
      --ORDER BY 'YtD P&L Value'
) AS Table1

UNION

SELECT
      Table2.[Instrument],
      Table2.[YtD P&L Value]
FROM
(
      SELECT TOP 200
            ISNULL(I.A_TKRCDE, I.A_INSNAM) AS 'Instrument',
            ROUND(SUM(A_ACCDAYPNLVAL), 2) AS 'YtD P&L Value'
      FROM T_ACC_AUMDET AD
      LEFT JOIN T_ATH_INS I ON AD.A_INSID = I.A_INSID
      LEFT JOIN T_ATH_INSTPEMAP ITM ON I.A_INSCLSCDE1 = ITM.A_INSCLSCDE
      WHERE A_AUMID IN
      (
            SELECT A_AUMID
            FROM T_ACC_AUM
                  where CONVERT(DATETIME,(substring(A_AUMDTETME, 7, 2) + '/' + substring(A_AUMDTETME, 5, 2) + '/' + left(A_AUMDTETME, 4)),103) BETWEEN {?1StartDate} AND {?EndDate}
            AND A_ACCID = '{?AccountName}'
            )
      --AND ITM.A_INSTPECDE <> 4
      GROUP BY I.A_TKRCDE, I.A_INSNAM
      HAVING ROUND(SUM(A_ACCDAYPNLVAL), 2) <> 0
      --AND ROUND(SUM(A_ACCDAYPNLVAL), 2) > 500000
      --ORDER BY 'YtD P&L Value'
) AS Table2
ORDER BY [YtD P&L Value] DESC