Daylite 3 uses a standard Cocoa preferences file.

You will find it at:
Home Folder -> Library -> Preferences -> com.marketcircle.Daylite3.plist

Note:
  *Write down all necessary information such as computer, database,
    username and password from the 'Connect to  Database' window in Dayltie
    before deleting this file.  As a backup measure,  you can even copy this file
    to a directory on your desktop prior to deleting this file.

  *Also, make sure that Daylite is closed before you delete this file.

Once you've removed (deleted) the file, launch Daylite.  If you want to get
back to that last database you where using, choose 'Connect to Exising Database'
on the First Run screen.