This specifies the new Phase IV synonym for the node.  Phase IV synonyms
 can be used in place of fully specified node names, particularly with
 applications that do not support full node names.

     SYNONYM new-synonym-name

 The synonym must be from 1 to 6 letters (A to Z) or digits (0 to 9), with
 at least one letter.  To explicitly specify that the node has no Phase IV
 synonym, use two quotation marks ("") for the Phase IV synonym name.  For
 example:

     SYNONYM MLHUB
     SYNONYM ""

 If the SYNONYM parameter is not specified, the previous synonym name is
 retained.