LYNN – With Republican challenger Richard Tisei criticizing him for not signing a Save Union Hospital petition, U.S. Rep. John Tierney stated he has made a commitment to ensure “the appropriate questions are raised” about plans to alter how the hospital operates.Save Union Hospital members, including state legislative candidate Aikaterina Panagiotakis Koudanis, have dotted Lynn with signs, and Tisei signed the group?s petition in July.Tierney, in a statement Tuesday, said that he has a role to play as a congressman when it comes to questioning Partners HealthCare about its plans for the Lynnfield Street hospital.?I think I can be most helpful in bringing together all of the parties involved from the community to Partners HealthCare to the state of Massachusetts, which will make the ultimate decision in this matter,” he stated.But Tisei campaign spokesman Charlie Szold called on Tierney to “…do what?s right and support the Union Hospital Advocates as they try to save the hospital.” Szold, in a statement, wrote that Tierney is “happy to sit on the sidelines” concerning Union Hospital.Tierney, in his statement, said he has not been idle in his efforts to closely question Partners? plans.?I want to ensure the appropriate questions are raised so the best possible outcome is achieved for Lynn and surrounding communities. That?s been my commitment, and that?s what I?ve been demanding of the state entities, which will be reviewing and making the ultimate decision on the proposal,” he wrote.Partners last fall unveiled plans to move surgical beds from Union Hospital to Salem Hospital and increase the number of psychiatric care beds in Union. The plan sparked criticism from residents living around the hospital, Mayor Judith Flanagan Kennedy and state legislators.Partners has yet to file detailed documents with state health officials explaining its plans, and North Shore Medical Center spokeswoman Laura Fleming on Tuesday said the “determination of need” documents “have been delayed for several months” due to “external regulatory activity,” including state and pending court reviews related to Partners? plan to acquire Hallmark Health Systems.