The MODIFICATION, IGNORE, FOLD, and [NO]TIE_BREAK options of
    the /COLLATING_SEQUENCE qualifier can also be used to modify the
    collating sequence. You can make more than one modification to
    the collating sequence. If you intend to modify any collating
    sequence, you must specify the sequence in the SEQUENCE option,
    even if it is the default sequence (ASCII).

    Because the FOLD, MODIFICATION, and IGNORE qualifiers are
    processed in the order in which they are specified, care should
    be taken when specifying the order of those qualifiers. Normally,
    FOLD should be specified after all MODIFICATION and IGNORE
    qualifiers to ensure that the effects of the MODIFICATION and
    IGNORE qualifiers apply to uppercase and lowercase characters.

    You can request that Sort/Merge ignore a character or character
    range within the given collating sequence by using the IGNORE
    qualifier.

    By default, in the Multinational collating sequence, Sort/Merge
    folds lowercase letters into their uppercase equivalents. If
    you want this folding to occur in the other collating sequences,
    you must specify a FOLD qualifier with the instructions for the
    collating sequence.

    Also, by default in the Multinational collating sequence,
    Sort/Merge uses numeric comparisons to break any ties in the
    collating values. Ties occur when two equal keys collate the
    same. If you do not want the default when using the Multinational
    collating sequence, specify the keyword NOTIE_BREAK. For tie
    breaking in the other collating sequences, specify a TIE_BREAK
    qualifier.