you can change the date on your Frontier flight ticket

Yes, you can change the date on your Frontier flight ticket, but fees may apply depending on when you request the change. If you modify your ticket 60+ days before departure, there is no fee. Changes made 59-7 days before departure cost $49, while those made 6 days or less incur a $79 fee. Additionally, if the new fare is higher, you must pay the difference. You can update your booking via Frontier’s “My Trips” section online, through the mobile app, or by contacting customer service. Same-day changes are available for a fee if seats are available.

Source: https://support.accountingseed.com/hc/en-us/community/posts/33958614268179--%F0%9D%95%B7%F0%9D%96%8E%F0%9D%96%9B%F0%9D%96%8A-%F0%9D%95%BB%F0%9D%96%8A%