Keep in mind, "agreement in concept" means they haven't finalized the language. Once the contract language has been approved by union reps, they'll have a tentative agreement. Once they have a tentative agreement, it has to be ratified by union vote. I wonder if the company is attempting to quell rumours spread to passengers about a strike by issuing this press release. In the past, I don't recall a PR going out until they actually had a tentative agreement.