Syntax:  DISABLE GRAMMAR PREFIX prefix

  Disables a prefix associated with a customized command language.

  LSE keeps the enabled grammar prefixes in a stack in the order in
  which they were defined.  This command deletes a prefix from anywhere
  in the stack.  If the prefix is the only one in the stack, no action
  is taken.  The default is to delete the prefix at the top.

  RELATED COMMANDS:

     ENABLE GRAMMAR PREFIX