A push to force Lincoln and Omaha to make significant changes to their pension plans for new police and fire employees met firm opposition from union leaders and some city officials during a legislative hearing Tuesday. But the proposal's backers called it essential to ensuring the state's two largest cities meet their obligations to cops and firefighters going forward. "It is not my intent to take any retirement benefits away from current plan members," said state Sen. Mark Kolterman of Seward, the measure's sponsor. "In fact, my motive for introducing this bill in to ensure that the current plan members receive what they've been promised."