\transpose question

[Mark Probert]

Hi. 

A question on transpose: I understand that "\transpose distinguishes 
between enharmonic pitches," however is there anyway to force a 
particular behaviour? For example, in the snippet below, when I have a 
movement from C to C# in the original key, and then go up a tone with 
"\transpose c d," I get "D and D#" (which is correct based on the 
provided notes and chords), however I want "D and Eb" (the other 
enharmonic).

Is there a way to do this?

Thanks .. mark.

--
\version "2.22"

melody = \relative c' {
  \clef treble
  c8 d ees f g4 r4 \bar "||"
  cis,8 dis e fis gis4 r4 \bar "||"
}

harmony = \chordmode {
  c1:m7 cis1:m7
}

song = {
  <<
    \new ChordNames \harmony
    \new Staff      \melody
  >>
}

trans = {
  \transpose c c { \song }
  \transpose c d { \song }
}

\score {
  \trans
}