I am claimed as a dependent on someone else’s return but did not select that i’m trying to amend my return but I am unable to locate the section where I would do so.

Go to MY INFO to change the way you answered the questions about whether you can be claimed as someone else's dependent.    If you filed first, the person who can claim you now has to file their own return by mail.  They do not have to wait for you to amend.  It will be months before your amended return is processed, so they can mail their return as soon as they are ready to put it in an envelope.

This is the personal info section.  Go back to your personal info page and select edit next to your name.  As you walk through you will be asked if someone else can claim you as a dependent. 

Click on My Info on the left side of the online program screen.  Edit your personal information.

On the screen Let's check for some other situations select that you can be claimed as a dependent.