function i2b2_set_role($user_name, $role, $project_id){
	/*
	 * Construct set_role XML call and attach to message_body parent
	 * <pm:set_role>
	 *  <user_name>mem61</user_name>
	 *  <role>DATA_AGG</role>
	 *  <project_id>ra_mart_test2</project_id>
	 * </pm:set_role>
	 * 
	 * Returns: Boolean true when user role is set
	 */
	global $i2b2_pm_uri, $i2b2_domain, $i2b2_service_account_id, $i2b2_service_account_pw;
	
	$request_xml = i2b2_header_xml($i2b2_pm_uri, $i2b2_domain, $i2b2_service_account_id, $i2b2_service_account_pw);
	$request_xml .= "<pm:set_role>";
	$request_xml .= "	<user_name>$user_name</user_name>";
	$request_xml .= "	<role>$role</role>";
	$request_xml .= "	<project_id>$project_id</project_id>";
	$request_xml .= "</pm:set_role>";
	$request_xml .= i2b2_footer_xml();
	
	$ch = curl_init($i2b2_pm_uri);
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
	curl_setopt($ch, CURLOPT_POST, true);
	curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: text/xml'));
	curl_setopt($ch, CURLOPT_POSTFIELDS, "$request_xml");
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	$data = curl_exec($ch);
	
	log_request($request_xml, $user_name . '-' . __FUNCTION__);
	
	return $data;
		 
}