I have met many people who push themselves to let go of their sorrow, their fears, their disappointments. They use rationalizing, avoidance, suppression as tools of letting go. Others fall headfirst into fantasy, imagination, even geographical changes to shed what bothers them, it never works.
Letting go happens spontaneously when you deeply realize that whatever you were so attached to no longer holds you hostage. It is there that the peace of surrender truly blossoms.