That is the thing. You cannot update a member tree. You can only update a new one and replace the old tree. It does not and never will work the way FTM or another genealogy program works because it is not a genealogy program as is FTM, PAF, etc. It is mostly a display program. You can enter and display what you have learned, you can link sources, you can upload and display photos and/or other documents but you cannot simply update your tree. That means when you replace your existing tree with a new one, you will need to reinvite anyone who was previously invited and you will also have to reupload photos and relink any census documents and/or other sources that you found on Ancestry. You will also get all the old hints you thought you had gotten rid of. In short, replacing a tree means all kinds of trouble. The best thing to do is to add your new data one person and/or one document or photo at a time. At this time, there is no option to upload a PDF document or photo. If you are talking about updating a gedcom to Rootsweb that will then show up on Ancestry, you can upload a new tree that will replace the old tree. These of course will not have photos, documents, etc.