What exactly are you trying to do?
The format of the date doesn't change its value at all. Dates are stored as
8 byte floating point numbers, where the integer part represents the date as
the number of days relative to 30 Dec, 1899, and the decimal part represents
the time as a fraction of a day.
Regardless of what your short date format is set to, Access expects the
dates in SQL statements to be in mm/dd/yyyy format. (Okay, that's not
strictly true: it will accept any unambiguous format, such as dd-mmm-yyyy or
yyyy-mm-dd. The point is, it won't accept dd/mm/yyyy if that's what you're
trying to do.)
If you are trying to deal to dd/mm/yyyy dates, you should probably read
Allen Browne's "International Dates in Access" at
http://members.iinet.net.au/~allenbrowne/ser-36.html