How do i change my reservation on jetblue mobile app without being charged

Hello, thank you for contacting Howly! I am here to help you today!
May I know your first name, please?

Nice to meet you, *****!

What service are you using for your reservation?

Would you like to reschedule the flight?:)

Okay!:)
Let me get back to you on this, and while I'm on it, please stay in the chat, thank you!

Thanks.
You can change your flight here: https://www.jetblue.com/manage-trips
Enter your Last name and Confirmation code/Ticket# an follow on-screens instructions.