element-expression Specifies the element or elements from which a generation is to be reserved. An element expression can be an element name, a group name, a wildcard expression, or a list of these separated by commas. By default, CMS reserves the most recent generation on the main line of descent of each element designated by the element-expression. remark Specifies a character string to be associated with the reservation and logged in the history file with this command. The remark is enclosed in quotation marks. If no remark was entered, a null remark ("") is logged.