A Conservatorship is a court proceeding in which a judge appoints a responsible person or conservator to care for another adult or conservatee. The probate court can appoint a conservator of the person, a conservator of the estate, or both, depending on the needs of the conservatee.
A power of attorney is a document you can use to appoint someone to make decisions and/or act on your behalf. The responsibilities of a fiduciary acting as an Agent under Power of Attorney can include financial matters, health care, medical treatment decisions and final burial arrangements.
In terms of duties, there is no difference between an Executor vs. Estate Administrator. The difference is the way in which they have been appointed. An Executor is nominated within the Will of a deceased person. If there is no Will, an Administrator is appointed by the Probate Court to manage or administer a decedent's estate.