Highmark Inc.'s contract with the Johnstown, PA-based Conemaugh Health System is set to expire, and those insured by Highmark Blue Shield already have received letters notifying them that their access to the system could be in jeopardy. But even if the two parties can't reach an agreement, most Highmark policyholders who use the Conemaugh system wouldn't see any immediate changes to their access or to the rates they pay. Both Highmark and Conemaugh say they hope to strike a deal on reimbursement rates between now and June 30, rendering moot the letters that have been sent out.