do I have to get new posts or can I just move them?
If you're looking to move a fence that's got posts in the ground to another location, then yes, you'll either need to move the posts (if they aren't anchored in concrete) or get new posts.
Hi Becky, you should be able to undo it where it attaches to the posts, this videao may help
As Becky said, you can reuse the posts if they weren't anchored with cement, otherwise you will need to replace them.
I believe your posts are secured into the ground about 2 feet. If you can get them out, you should be able to move them.