Utah Code § 75A-9-118: Limitations on powers.

(1) If an individual has a long-term disability requiring routine treatment by artificial nutrition, hydration, or mechanical ventilation and a history of using the treatment without objection, an agent or default surrogate may not consent to withhold or withdraw the treatment unless:

(a) the treatment is not necessary to sustain the individual's life or maintain the individual's well-being;

(b) the individual has expressly authorized the withholding or withdrawal in a health care instruction that has not been revoked; or

(c) the individual has experienced a major reduction in health or functional ability from which the individual is not expected to recover, even with other appropriate treatment, and the individual has not:

(i) given a direction inconsistent with withholding or withdrawal; or

(ii) communicated by verbal or nonverbal expression a desire for artificial nutrition, hydration, or mechanical ventilation.

(2) A default surrogate may not make a health care decision if, under other law of this state, the decision:

(a) may not be made by a guardian; or

(b) may be made by a guardian only if the court appointing the guardian specifically authorizes the guardian to make the decision.