If you want to get this achievement without the hassle of changing your date. Make sure you first contain halo Reach downloaded on the halo MCC. Plan on your calendar (or preferably on your phone as it will remind you) the next 14th of any month to remind yourself to play halo Reach on the MCC.
Before then have some fun playing Halo MCC whether its Halo CE, 2, 3, ODST, 4 or heck even spartan ops. Once the day (the special 14th) arrives play Halo Reach on the MCC. You have plenty of options on Halo Reach. You can play the campaign solo or co-op, or try your impressive skills at some multiplayer or you can even enjoy some classes nostalgic firefight, whatever options you decide to play on Halo Reach the Achievement should pop straight away.
Note: If your offline when trying to get this achievement, the achievement will not unlock and you have to wait a whole month to play Halo Reach on the MCC on another 14th date. So make sure you have an internet connection.
PS: Halo Reach came out on the 14th of September 2010, so this achievement is in reference to the release date.
PPS: This is my first achievement solution, make sure to comment some feedback so I can improve. Thanks guys.