Originally Posted by
Trustee
... I wanted change the outward leg to LHR-LAX on 04-Jun-12 (with a separate one-way car rental to Las Vegas).
This statement makes your entire dialogue with UA agents irrelevant. When you plan to change the outbound flight, you essentially need to EXCHANGE your current ticket for a completely new one, with a change fee. It is not a CHANGE based on fare rule terminology.
The first agent might have looked under CHANGES and misinterpreted
A. CHANGE MADE TO OTHER THAN THE FIRST TICKETED FLIGHT...
to mean "no changes can be made to the first ticketed flight," which is not the case.
Without going into any more needless detail, you have been given wrong information by the first UA agent, and the others had just followed along. What you are doing constitutes a ticket EXCHANGE, and there is nothing in the rules that says you cannot do that. In fact, I dare say that no published UA fare prevents the customer from exchanging an unused ticket for a new one.
Whatever "international fare condition" means, I don't know nor care. It's gibberish.