In movable Do, what can be changed while retaining the names Do, Re, Mi?

In the movable Do system, the names Do, Re, and Mi are assigned to scale degrees relative to the tonic, or home sound. This means that regardless of the key in which the music is played, the syllables can remain consistent as they reflect their function within the scale rather than a fixed pitch.

When the starting or home sound changes, the system adapts to this new tonic while still using the same syllable names to denote the scale degrees. For example, if you start a scale on C, C becomes Do, D becomes Re, and E becomes Mi. However, if you transpose the music to start on G, G becomes Do, A becomes Re, and B becomes Mi, yet they retain their functional names.

This highlights that the names can indeed change their pitch depending upon the tonal center while maintaining the same relative distance and function, which is a key component of the movable Do approach. Other factors, like rhythm, key signature, and tempo, do not influence the naming of the notes according to the movable Do system.