Article 15 lists several duties of the Competent Authorities under the Agreement.  It authorizes them to negotiate any administrative arrangements that may be necessary to implement and administer the Agreement.  It also requires them to designate liaison agencies to have primary responsibility for coordinating the benefit claims and coverage determination procedures of the two countries.  Under Article 2.1 of the Administrative Agreement, as amended by the Supplementary Administrative Agreement, the U.S. liaison agency continues to be SSA. The United Kingdom has six liaison agencies.  One of these handles all matters except for the coverage provisions of the Agreement and providing  U.K. insurance records for U.K. disability benefits claims.  Another handles those two responsibilities.  The other four are the social security authorities of Northern Ireland, the Isle of Man, Jersey and Guernsey.   Article 15 also required the Competent Authorities to notify each other of the measures they took unilaterally to implement the Agreement, as well as any changes in their social security laws that might affect application of the Agreement.   Thus, in October 2008, U.K. social security authorities notified SSA of the changes in U.K. social security programs described in the annotations for Chapter B.