Fill in the Variant Generation Name field to create a
  variant generation.

  If two or more users have concurrently reserved the same
  element generation, only one of the replaced generations
  can be on the same line of descent. Thus, no more than
  one can be replaced as a main line generation and the
  rest must be replaced as variants.

  The Variant Generation Names are limited to
  alphabetic characters (A through Z) and underscore
  characters with a maximum length of 255 characters.
  CMS labels the  variant generation by appending the
  Variant Generation Name and the number 1 to the generation
  number.  For example, if you reserved generation 2 of an
  element INIT.BAS, you could create a variant 2CHANGE_ABC1,
  where 2 is the generation number, CHANGE_ABC is the
  variant name, and 1 is the appended number.