AirTran: Boston passengers with flights booked for April 15-17 may reschedule their flights up to three days after their original scheduled departure date.
American: Boston passengers with flights booked for April 15-17 may reschedule their flights through April 20. The ticket reissue fee will be waived for one change.
Delta: Boston passengers with flights booked for April 15-17 may reschedule their flights through April 20. Ticket reissue fees will be waived, but a fare difference may apply.
JetBlue: Boston passengers with flight booked for April 15-17 may reschedule their flights through April 21. Both change fees and fare differences will be waived. For travel beyond April 21, the change fee will be waived, but a fare difference may apply.
Southwest: Boston passengers with flights booked for April 15-17 may reschedule their flights to within 14 days of the original travel date. Southwest has a standard policy of not charging change fees.
United: Boston passengers with flights booked for April 15-17 may reschedule their flights to within one year of the date of ticket issue. The change fee will be waived, but a fare difference may apply.
US Airways: Boston passengers with flights booked for April 15-17 may reschedule their flights through April 21. The change fee will be waived, but a fare difference may apply.
As always, check with your airline directly for any changes to the issued waivers.