How does a person void a revocation of POA that she made?

I have a friend with no family who designated me as POA, health care proxy, decision maker in her living will in 2009, and then at a time in 2011 when she had a boyfriend, had her lawyer revoke that POA, as well as powers previously provided to me in the Living Will and Health Care Proxy. She is no longer dating this boyfriend and still expects that I am designated for what I was previously. I came across the revocation and letter from her attorney and asked her about it, and she did not remember doing it and said to just rip it up. I'm thinking that just ripping it up does not reinstate me to do anything. It makes me very nervous. I do not think she wants to pay her attorney to do a new POA, so she said she would write on the Revocation that she voided it and reinstated me and sign it, but I am not convinced that this is legal.