.Replace Not Replacing

I have this code to find all query's in a workbook and replace the database name with the "new" database name.  All values are being passed appropriately with acceptable values and the code executes fine (even when I step through line by line to verify each point is being hit).  The problem that I have is Sheet2 is not actually being replaced, even though when I step through the code it seems to replace...

oWB = (Excel._Workbook)oXL.Workbooks.Open(path + template + ".xls");
oWS = (Excel._Worksheet(oWB.ActiveSheet);
oXL.Sheets[2].Select();
foreach (Excel.QueryTable qt in oWS.QueryTables)
{
    qt.Sql.ToString().ToUpper().Replace(template,newOne).Replace(template.newOne);
}
oXL.Sheets[1].Select();
foreach (Excel.QueryTable qt in oWS.QueryTables)
{
    qt.Sql.ToString().ToUpper().Replace(template,newOne).Replace(template.newOne);
}