You can export and import the original family tree into your Family Echo account to create a copy. To do this, please use the 'Download/export' button at the bottom of the left-hand panel and choose to save the family information in a GEDCOM or FamilyScript file.
The go to 'My Account' in the top right of the page and choose 'Create new family'. In the left-hand panel you will now see an option to import the file you just created. You can save this copy of your family tree to your account and make the changes you want.