A patient in hospice can leave at any time whether they have decided to resume curative treatment or want to pursue experimental measures. If a patient is showing signs of recovery, they can be discharged from hospice. You can always return to hospice if the illness progresses later on.
You do not need a doctor’s consent to leave hospice—this is called “revoking” hospice and can be done by a patient whether they decide to try to fight their illness again or if they want to transfer hospice providers. Hospice is always up to the patient and whatever makes them comfortable. However, revoking hospice also means revoking any benefits that they may be receiving from Medicare including home medical equipment and supplies, supportive services, home visits, and more.