VMS Help CMS, REMOVE, ELEMENT, Qualifiers, /IF_PRESENT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Directs CMS to remove the element from the group if it belongs to
    the group. If the element does not belong to the group, CMS takes
    no action and does not return an error. When you use wildcard
    characters in the element expression, /IF_PRESENT is the default.