How long ago did your mother give POA to your sister? If your mother is of sound mind your mother could sign a new POA giving it to you and evoke the other one. If she is not of sound mind then you can go to court and get guardianship which trumps the POA or get her to sign a durable power of attorney. In some states there can be two POA's. I am in a similar position and will be going to a lawyer soon since I don't think my sisters DPOA is legal since my sister printed it off the internet for free and while my mother was living with me picked my mother up for a visit and had my mother sign the paper and had it notorized. My mother was not of sound mind when she signed it. I am going to find out what I have to do since my mother is not of sound mind and can't sign a new one for me now. I may go for quardianship.
Patsey, do you know if there is a back up person mentioned in the Power of Attorney? Usually people will elect two persons, one primary and one secondary or both to represent as equals.
Since Mom wanted you to be her caregiver, it is best to work as a team with your sister for your Mom's best interest.
Since Mom wanted you to be her caregiver, it is best to work as a team with your sister for your Mom's best interest.