I sort of feel that this discussion has missed a few points involved in embouchure changes and playing the horn in general that are common to any embouchure that may be helpful to someone making a change.  Electing  to change your embouchure is the result of dissatisfaction with your current playing; either range, sound, or flexibility I think.  Selecting how you *need to* change may affect *what you change to* and should be overseen by a good teacher.  I tend to agree with Eddie that there is no "one way".
People may have different physical attributes that would affect how you *can* play.  But, IMO there are common attributes a good embouchure or method must have and common ways in which you should approach it.

I am now in my 3rd year of an embouchure change.  Well, actually, I've been playing for about 3 years (my second trumpethood) and I have been searching and learning for that long.  I've read all the suggestions about embouchure and how to practice, yaddita, yaddita, yaddita...  I knew I should pay attention but, hey I'm an independent kinda guy.  I can find my own way. (He said boldly; if ignorantly.)   Well, maybe.  Then again, maybe I *should* pay attention.

I am definitly not an expert and welcome any comments, corrections or suggestions from others.  But, from my perspective the common elements that we need to pay attention to when learn to play, or when we change an embouchure include:

- -- Strive for ease.  That is, try to adjust your embouchure for each note so that playing that note is as easy as possible.

- -- Make sure each tone is centered and full.  Playing is very tiring if you have to fight the horn.  Work *with* the horn.  This is particularly important when playing the high range.  Try playing an A (in the staff) open (no valves).  You gotta work pretty hard to do it.

- -- Minimize pressure on the lips.  Playing the higher range is very difficult if you use too much pressure.  Playing with no pressure is not workable either but try to minimize/optimize it.

- -- Be flexible.  Make sure that you always *move* your embouchure.  It seems a silly statement on the face of it but it is something I have learned (am learning) the hard way.  What you move likely depends somewhat on the style embouchure you are using/learning.  I'm no expert, but, a static embouchure is an invitation to mouthpiece pressure IMHO.

- -- When playing an exercise, make sure you keep in mind what the exercise is designed to do for you.  The Claude Gordon book "Systematic Approach to Daily Practice" is good at doing this.  Each time an exercise is presented, the specific aspect of the embouchure that they are designed to address is stressed.  It pays to keep this in mind and concentrate on it.  Try to engrain these in all your playing.  At first you may be able to concentrate on only one aspect but they will eventually become automatic.

- -- Relax.  Playing should be fairly easy (strength-wise that is). If you think playing the higher range will be hard, it will be. Tension (especially in the throat and mouth) will take over and defeat your best
efforts with your embouchure.

- -- Rest.

I can't tell you how many times I've heard this.  Mostly I thought "Yeah right.  Who has time to rest *and* play.  I'm lucky if I can find enough time to practice."  But it helps tremendously.  From my perspective playing the trumpet is not about brute force.  I used to think  that to play the high range you needed a Schwartzenegger embouchure.  Now I believe it is really a Tai Chi embouchure; one that is well trained and subtle.  The "trick" to playing is not in developing huge strength (although moderate strength is important).  The "trick" is to learn to control the very subtle changes in your embouchure that allow you to move from tone to tone easily.
 

Praticing without resting will lead you to abondon those subtleties for brute force.  It is hard to make a subtle movement with a highly fatigued muscle.  Try running up stairs for a few minutes and then stand with your knees slightly bent.  Not easy and if you are not used to doing this kind of exercise, your legs will actually shake.  Rest and it's easy.  What you are trying to learn is subtle control.  Not easy on muscles fatigued with overwork.  Endurance is another issue that can be addressed separately but is also affected by how efficiently you play.  If you learn to play while you are tired (no rest) and develop bad habits, that is the way you will always play.  Learn to play correctly, and only correctly (with rest so you don't resort to behavior made necessary with fatigued muscles).  Then, when you play, you will always play that way.

As always, if I'm all wet, flame me. That help should dry me out a little. :-)  All of this is only my perspective; the perspective of a learner and searcher.  Commments welcome.  (Please be gentle.)

FWIW

Tim Hutson