This Practice Note provides an overview of the process and standards for modifying or rejecting Collective Bargaining Agreements (CBAs) in a Chapter 11 case under section 1113 of the Bankruptcy Code. This Note addresses the procedures and substantive requirements for modifying and rejecting CBAs in bankruptcy, including the applicability of section 1113 to expired CBAs, notice and hearing considerations, short-term emergency relief from obligations under a CBA, postpetition performance under CBAs, consensual modifications to a CBA, priority of claims arising under CBAs, effect of rejection of a CBA, section 363 sale considerations, plan confirmation issues, and rejection of CBAs in Chapter 9 cases involving municipalities.