It's a Billy Cook western saddle, it's not changeable sadly.
If your saddle hasn't got a changeable gullet you could try a half pad saddle riser. I am sure you can get sheepskin, foam or gel ones I find my sheepskin one is very good for this.
Has the saddle got a changeable gullet? If not your saddler should be able to change it, this will allow you to change how it sits on the horses wither