Since some people can't get past paragraph 3 of an article the onus in journalism is on the author and editor to not leave any wrong impressions early on. This isn't a drama. The last sentence of paragraph 3 is as follows:
The gate agent told her that her reservation had been canceled. Traveler Help Desk, the online agency that sold the ticket, had rescinded it because the landlord made a change directly through United — even though United had assured the landlord that it was not a problem to do so.
It could easily as read as follows with no discussion of being "assured" by United (which is a throwaway to put some blame on United early and then lead to the GA actions):
The gate agent told her that her reservation has been canceled. The landlord had bought the ticket from an online agency, Traveler Help Desk, and made a legal ticket change with United. However, Traveler Help Desk then rescinded the ticket with no documented warning to the landlord even though the change did not affect them financially.