Find the will and confirm who has authority.
Before anything else, locate the will. In Utah, the will names a personal representative, sometimes called an executor. That person is the only one who can sign a listing agreement, accept an offer, or sign a deed at closing. If there is no will, Utah intestacy law dictates who can petition the court to be appointed personal representative, typically a surviving spouse or adult child.
Once probate opens, the court issues Letters Testamentary (with a will) or Letters of Administration (without). That document is what every title company, lender, and listing agent will ask for. No Letters, no sale.