Letters of Administration is a document issued and signed by a judge in probate proceedings which provide "proof of authority" for the executor to act on behalf of the estate. The only way to obtain the Letters of Administration is to file a petition for probate.
However, you likely will not need to do that. Most states have some form of "small estate procedure". California has such a procedure. Here is a link to the form: http://www.caldocs.com/resources/probate-codes/Small-Estate-Affidavit.pdf
If your father died in California, this form should work.
This does not constitute legal advice and no attorney client relationship exists. Always seek advice from a local qualified attorney.
Your situation could either be very simple or very complex. You simply have not provided enough facts to make a determination of which way to go. If your father was a resident in New Mexico at the time of his demise, then you are certainly going to have to process this claim in New Mexico. If your father was a resident in California, then there are summary ways to process probate claims for limited value Estates. You will certainly fall within the parameters. In regard to requirements in the state of New Mexico, this is a whole other issue, and you would have to look to the new departmental regulations that presently exist in New Mexico law. If your father was a resident in the state of California, hopefully an axillary probate will not have to be established in the state of New Mexico. Based on the fact you are dealing with potential California authority and New Mexico authority, and potentially having to satisfy both of these jurisdictions, this certainly could compound the difficulty of the situation. If your father's last residence was in New Mexico, you certainly are going to have to consult with an attorney in New Mexico. I would strongly suspect they would have summary procedures for resolution of small claims.
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