Flight tickets

A question about : Flight tickets

I purchased a package hol inc flights & want to upgrade my flight but the Travel Agent say that a high charge will be imposed and will not allow me to speak with the Company through which the tickets were purchased.I maintain that the ticket belongs to me and I can change it if I wish. Am I within my rights?

Best answers:

• I expect the airline will just refer you back to the agent as that is who you booked with
  Are you wanting to upgrade with miles or money? with money the cost may be the fare difference to the higher class which could well be significant
• What exactly have you booked and who with?
  And what are you looking to upgrade to and from? This will help people give more specific advice.