Hi, Obviously you need to roll the time 12 hours ahead. If the watch doesn't receive the Atomic signal properly at first, go to page three of your manual, and try doing it manually following the detailed procedures there.
If you don't have the manual, get it here:
http://world.casio.com/wat/download/en/manual/
Take the four-digit (3070) module number from the back of the watch, enter it, and download a PDF of your watch setting-instructions/manual.
I hope this helps you. Thanks, Bill