What if the original person in the booking changed their name by deed poll to the new person to be in the booking? The travel agent would surely be obliged to change it to the correct/new name - for no charge?

As per title(!). Tickets are approx £600 each - 4 going. One person cannot go now, so it was intended for someone else to come. Apparently it is not possible to change the name on the holiday - but it is no problem to cancel & rebook apparently. For this, it means losing the full cost of one ticket and paying nearly £500 for a new one. This seems to be close to fraud on their part... Any legal possiblities (unfair contract / penalty?)