To have reservations means to hold something back, to not be 100% for recovery, but instead to hold on to the possibility of returning to the behavior if necessary, or under the "right" circumstances. Reservations aren't all bad, because they mean that the dominant motivation is toward recovery - the reservation is there "in case." Sometimes reservations are what make it possible for someone to move forward in recovery when they've previously been paralyzed by their ambivalence. For example, someone with anorexia once told me: "It's ok to gain weight now, because I know I could lose it again. It doesn't have to be permanent." While that may sound unnerving, I also know that gaining weight and going through the motions of recovery can bring about biological changes that may put her in a better place to embrace recovery.
Of course, while reservations in recovery may be better than no recovery at all, they can still be problematic. They prevent a full and lasting recovery, and the only way to make one's recovery full and lasting is to come to terms with - in other words, let go of - the reservations. Easier said than done, right?
The first step is to acknowledge that there are reservations. Because reservations make people anxious, there is a tendency to mislead both other people and oneself about the strength of one's commitment to recovery. Normalizing reservations can help people move past denial.
Once people acknowledge having reservations, it's time to get to the bottom of what they're about - what is the purpose, meaning, or symbolic value of the reservations? Of the behavior? What does the person fear if s/he lets go of reservations?
Just naming that underlying significance can make it easier to let go of reservations. If that's not enough, though, the task becomes figuring out other ways for the person's deeper needs to be met without resorting to problem behaviors.
All the while, however, it's important to remember that the person may have slips or small relapses along the journey of recovery, and reservations can resurface, or new ones can come along. Recovery is not linear; it's a winding road with unexpected pitfalls. However, it's also an opportunity for deep learning and growth that carry forward, even through the bumps on the road.