Colo. Rev. Stat. § 38-30-131
Every such commissioner, before performing any duty or exercising any power by virtue of his appointment, shall take and subscribe an oath or affirmation, before a judge or clerk of one of the courts of record of the district, territory, state, or country in which such commissioner resides or before any ambassador, minister, consul or vice-consul, consular agent, vice-consular agent, charge d'affaires, or any diplomatic, consular, or commercial agent or representative of the United States appointed for the foreign state or country in which such commissioner resides, well and faithfully to execute and perform all the duties of such commissioner under and by virtue of the laws of the state of Colorado, which oath, and an impression of the seal of office, together with his signature thereto, shall be filed in the office of the secretary of state of this state within six months after the date of appointment.
C.R.S. § 38-30-131