Q. My son bought a London-Buenos Aires ticket on Iberia through an agent. Because his plans were fluid, he specified a ticket that would allow him to change the return date for a set fee. Shortly before departure, he was told his flight would be transferred to Air France because of a strike at Iberia. Now he has asked to change the return date, only to be told that it is fixed and could not be changed. The company says Paul should have asked but it was the last thing on his mind. Does the agent have any obligation? Phil Galbraith

A. It is commendable for an agent to avoid possible problems by offering an alternative flight to a strike-threatened departure. But the company should have taken care to inform your son of any material changes that the switch would involve. Moving from a changeable inbound leg to a fixed date should certainly have been mentioned, especially since your son specifically asked for a flexible inbound ticket.

The choice offered to Paul should have been as follows: keep the Iberia flight, and accept the risk of a delay of several days; or fly out on a guaranteed Air France departure but surrender flexibility coming home.

If you are confident about who said what when, write a stiff letter (ideally supported by email correspondence), threatening legal action unless the firm allows your son to change the flight at the fee originally agreed.