You don't. You can't. The only way to translate a DateTime into a specific format is to convert it to a VARCHAR or other "string" data type. This means that it is no longer a DateTime. It is a VARCHAR.
Here is the code to convert into 'mm/dd/yyyy' format:
select right('0' + rtrim(month(@d)),2) + '/' + right('0' + rtrim(day(@d)),2) + '/' + rtrim(year(@d)).