There are two basic ways of doing this.  As a note, both ways actually convert the date into a string value.  As long as you just use this for display, and don't try to do anything like group on the value, it shouldn't have any effect.

The simplest function is just to use CStr.  If you look it up in the help file, it will tell you about converting date (or datetime) values to strings.  It will also guide you to a page with all the various options for how to format your dates.

The more complex, but more flexible, method is to use the DatePart function to separate your date into its component parts, and build whatever string you choose.  Check out the DatePart function in help.  Also check out the Year, Month, and Day functions, as they are shortcuts of common DatePart functions.