Detroit's new state-appointed emergency manager yesterday disavowed letters sent by the mayor's office saying that the city would stop honoring contracts with its police, fire and paramedics' labor unions, Reuters reported today. The apparent miscommunication between Mayor Dave Bing and Kevyn Orr, the former bankruptcy lawyer brought in to clean up Detroit's finances, highlights the challenges Orr may face as he assumes increasing power in the biggest state takeover of an American city in more than two decades. Written to Michigan's five commissioners of employment relations, the letters declared that as of March 28, the destitute city considered itself in receivership status and no longer bound by its union contracts. March 28 is the date when a Michigan law went into effect giving the emergency manager wide powers, including the authority to abrogate union contracts. Orr's office said that the emergency manager had no warning that the letters would be sent.