Transpose - output to a new .ly

[Hans Forbrich]

Is it possible to have the transposed music output to a new lilypond .ly
file?

I've keyed in a piece where the score was in "ges minor" (already
transposed).  This means there are an awful lot of  'es' and 'is' ... it
would be nice to get a fresh .ly transposed to a 'cleaner' key for
maintenance reasons.  Or just return the piece to the composer's
original "A minor" without having the  (perceived?) overhead of
transposing.

Thanks
/Hans