If it's parked, then it has no files.
So when you delete it and re-park it, you don't have to worry loosing data.
Now, there is another trick.
Under /home you will see the user directories that are the username under Accounts.
You can use CWP's File Manager and rename the user you want to try to save from like user123 to a non account like jdoe.
Create the new account and then use File Manager to delete that directory and then rename jdoe to the new user.
Then run fix permissions.
* DISCLAIMER: I make no warranty data may be lost. *