Change What?
First let me explain that in a final sitting with the sculptor there is an adjustment period. Moments when you first see the sculpture and you must stop, take time with the sculpture and absorb it. In the case of creating a sculpture in memory of a deceased loved one this can have many other emotions attached to it.
Please be aware that when you do come to a final sitting it is important to be as explicit in your thoughts as possible. Don’t just say it looks strange, say, there looks like there might be too much distance here, or the right eye looks closed and should be opened more. Then let the artist do their work. You see when you work in three dimensional work the artist might have to translate what you say and see if there is something else that is off. If the face looks to narrow, it could be the placement of the ears. If the eyes look too close, it might be the width of the nose. The artist must assimilate your comments and perform their magic.