Not sure exactly what you are trying to do but you probably want to use the Weekday function. Eg, to only display a date if its a Tuesday:
=iif(Weekday(MyDate)=3, MyDate)
Note, sunday = 1, monday = 2 etc. You can change the default by indicating the required first day of the week in the function call (see the help page in Access). Best Regards,
Mike