I created a tree on familysearch.org for a friend. Now I would like to begin one for myself. How do I begin a new tree without deleting the original tree?
Family Tree is just one large database that all entries are in. So you just continue entering in information. You can start a new branch of this one-world, universal tree for someone that you don't have family connection for at this point by using the "Add Unconnected Person" link at the bottom of the Recents menu.
However, I hope you are not going to run into an issue that has caused a problem for some people in the past. Please hold on for bit of a complicated explanation.
First, some basic information that you are probably already aware of.
Living people entered by you are private and their information can only be seen by you. When they are marked deceased, then they enter the general public space where anyone can see them.
When you first opened your Family Tree account, a ID number was assigned to you which is only you and is always the basic root of your connection to Family Tree. This ID and its associated profile can be seen under your Account setting. So the first thing you need to do is click on your name in the upper right corner of any page and in the menu that opens, click on Settings. The Account page will open. Scroll down the the Family Tree Preferences section which will look like this:
Click on Edit to open it to this:
If that person and ID is your friend, what you need to do is create a new profile for your friend as a child of his parents. then transfer all the information for your friend, all data, all sources, and all memories, to that new ID. Then move all relationships for spouses and children to that new version of your friend, detaching them from the current version. Detach the original ID from his parents Then on that base ID for your account, change the name and all information to you.
Then proceed from there.