You don't need to amend your return. You cannot be a dependent of yourself. You are the taxpayer, and someone else that you support (not a spouse) can be a dependent.
If you need to amend for another reason, you will be able to amend once your original is processed. Check your filing status to see when it is accepted and you have either received your refund or paid the tax due. Then file an amended return if needed.
You can find more details here: TurboTax: Rules for Claiming a Dependent on Your Tax Return.
