You can download your Ancestry tree in gedcom format to your computer and then use the import function in Legacy. Once it is imported, Legacy will save it as a Legacy file leaving you with both the gedcom and legacy files on your computer. You can then delete the gedcom if you wish or keep it as a backup. I have not tried this lately so am not sure if photos and documents are downloaded in the gedcom or not. Experimentation is always fun though. ;-) Hope this helps.
Mr. Cann raised the question whether photos and document attachments come along; I don't think so. At least not when I have done this procedure. Is there something we are missing?
No photos or other documents saved will be downloaded into a GED file. Also, if you have stories either put them into notes or save them to your computer separately as they will not be included. However, anything you put into the "Notes" field in Ancestry will be transferred into a GED file and you will find those in your Legacy file when you download in "Notes".
I am always updating my file on Ancestry.com and downloading a GEDCOM file into Legacy I make sure I do it often so I always have a backup of my large file on Ancestry. What I don't like is that if you do the reverse and upload your Legacy file as a GEDCOM into Ancestry you end up with a date format I don't like that I don't believe is correct. For example, a date might appear as 4-8-2009. You can't tell if that means Aug 4 or Apr 8. I am consistent with my dates and put in the day, month and then the year (ex. 19 Aug 2009). There may be a way to assure this format transfers before uploading but I don't know if you can. Someone might have the answer to that one.
Anyway, sorry but no photos or documents saved in a graphic or a WP format transfer so it's a pain. You gotta load those in separately into Legacy.
In addition to my last comment you will, however, see a link on Legacy to all your graphic files and stories you put on Ancestry listed under each indivudual but not the actual files as I said. It is a good way to check to make sure when you want to add those back into Legacy after downloading your GEDCOM file in order that you don't miss anything.
I recently, after my cousins begging me to do so, uploaded my Legacy file to Ancestry. I have several issues with Ancestry (like how did I end up with 22 separate branches when I started with one) but my question here is this: If I enter new info to my tree into Legacy & then want to add that additional info to my Ancestry Tree do I have to enter it manually? I don't see any way to upload this new information without starting a new tree which is not an option because then I will loose the "member connections" I have made. Any thoughts? -Susan