A/RES/56/242 4. Notes with satisfaction that the Secretariat took into account the arrangements referred to in General Assembly resolutions 53/208 A, 54/248 and 55/222 concerning Orthodox Good Friday and the official holidays of Id al-Fitr and Id al-Adha, and requests all intergovernmental bodies to observe those decisions when planning their meetings; 5. Reaffirms its decision that the headquarters rule shall be adhered to by all bodies, and decides that waivers to the headquarters rule shall be granted solely on the basis of the calendar of conferences and meetings of the United Nations as recommended by the Committee on Conferences for adoption by the General Assembly; 6. Also reaffirms the general principle established in the headquarters rule and, in particular, that all meetings related to the environment and to human settlements that are organized by the United Nations Environment Programme and the United Nations Centre for Human Settlements (Habitat), respectively, should be held at Nairobi, headquarters of the Programme and Habitat; 7. Further reaffirms the relevant provisions established by the General Assembly in its resolution 50/11 on multilingualism; 8. Requests the Committee on Conferences and the Secretary-General, when planning the calendar of conferences and meetings, to avoid simultaneous peak periods at the various duty stations and to avoid scheduling meetings of related intergovernmental bodies too closely together; II Utilization of conference-servicing resources and facilities 1. Approves the guidelines on limiting meeting duration contained in the annex to the present resolution; 2. Requests the Secretary-General to enhance further the established practice of workload sharing among duty stations in documentation services as a means to improve the utilization of conference-servicing resources, and to include information on these efforts in the context of a single, comprehensive report to be submitted to the General Assembly at its fifty-eighth session; 3. Also requests the Secretary-General, bearing in mind the recent organizational changes, to ensure that the Department of General Assembly Affairs and Conference Services of the Secretariat is considered the appropriate executive authority to oversee, coordinate and enhance the global management and delivery of United Nations conference services, under the legislative authority of the General Assembly and through oversight and examination by the Committee on Conferences; 4. Reaffirms the terms of reference and main functions of the Committee on Conferences as formulated in section I, paragraph 1, of resolution 41/213 and in resolution 43/222 B; 5. Welcomes the improved participation of observers in the work of the Committee on Conferences, the changes in the procedure governing the participation of observers and the decision of the Committee to keep this procedure under review; 6. Requests the Secretary-General to submit a report to the General Assembly at its fifty-seventh session on the mechanisms available for addressing the concerns of Member States about the efficiency, quality and delivery of conference services, including information about the way in which the concerns of Member States are recorded and reported, and on the grouping of these issues in reports to the General Assembly; 2