this is a quote from reddit user peanutsformonkeys
OK, if you have the current aeond fully synced up, you could, once you have the rebase aeond built, sync from your local up-to-date aeond with the --add-exclusive-node 127.0.0.1 flag
looks like you don't have to DL the entire blockchain. I don't think that the rebase is ready for the aeon mainchain yet.