I completed my Invisalign treatment with an authorized Invisalign practitioner. I wasn't 100% satisfied with the results, but I admit the end result is much better than when I started. I ordered and received retainers from this practitioner. I was wondering, if I change to a new Invisalign practitioner, would they be able to order the same set of retainers, based on the the original impressions sent to Invisalign or would I have to take new impressions. Thank you in advance for your reply.