Not OP but my tip is to take a weekend or some other time without obligations and stay up 1-4 hours later each night until you have rotated around to the correct schedule.
The other way is to develop a sleep debt until you can sleep at your desired time, and set an alarm to prevent yourself from oversleeping and falling back in to your normal routine. This will also lose you time out of your normal schedule, and is pretty terrible-feeling to boot, but it doesn't require quite as long.
Sleep physicians or sleep therapists are good about setting this kind of stuff up, if you have reasonable and inexpensive access to medical help.
The other way is to develop a sleep debt until you can sleep at your desired time, and set an alarm to prevent yourself from oversleeping and falling back in to your normal routine. This will also lose you time out of your normal schedule, and is pretty terrible-feeling to boot, but it doesn't require quite as long.
Sleep physicians or sleep therapists are good about setting this kind of stuff up, if you have reasonable and inexpensive access to medical help.