One of the things that may take some getting used to in using FamilySync instead of TreeSync is that you no longer need to break links. Almost ever. That's because each Ancestry tree can now link to multiple FTM trees, so it's just not necessary any more to break an old link to download a tree to a new computer.
So, for example, when you install FTM 2017 on a new computer, your instinct may be to break the old link and then download a fresh copy onto your new computer. Don't do that. You shouldn't even think of breaking that link to move your tree to a new unit. Instead, you should make a Backup on the old computer, move it to the new computer on a flash drive, and Restore it there.
The result? BOTH trees will be linked to that same Ancestry tree, and you'll have saved a lot of time uploading and downloading. Get used to it. That's FamilySync. Three computers. One Ancestry tree. No problem.
Here's how it works:
Not sure how to make a manual backup?
Here's a link with easy-to-follow instructions on how to make a backup ready for use in multi-computer sync: