Recently, by mistake, the private key of my name delta is a friend, and I would like to know how I change, thanks for the attention.
Its already been said on MEW that you should keep you private key on yourself and you and only are the responsible for your own security.
For the question your asking that If there is a chance to change your private key?
the answer is Its impossible to change your private.
Why would you change if you can create another wallet, just create a new one its the easiest solution for your problem.