60da59b1_Frontier_Travel_Policies__Documentation_required___
[Type of Emergency Event...] Serious illness or injury that prevents the ticketed customer from traveling for the duration of the validity of the ticket (one year from original date of purchase) [Options available to you...] Cancel the unused portion of a ticket and receive a full refund (less a refund processing fee of $50 for Economy tickets) [Documentation required...] 
A doctor's note in writing specifying that you are unable to complete travel during the ticket's validity period. The certification must be signed and dated on the physician's or hospital's letterhead.
Frontier Travel Policies
Documentation required...