It seems Dorico does not allow you to respell chord symbols. Am I missing something?
I needed to be in C# as opposed to Db as the song alternated between the keys of C# major and C# minor. Where Db would have been preferable under normal circumstances, this was a rare case where C# major made much more sense.
I was able to change the key of the Db section to C# and also change the note spelling with no problem. However, no matter what I tried, I could not get the chords to respell. I ended up having to rewrite each one individually. That was a grind with 250 of them.
OK, try using Write->Transpose instead. Transposed an Abmaj7 to a Gbmaj7 with this setting. Use the calculator to the right. The Shift-i ,t-2d work for enharmonic spelling at least.
Shift-I is applied to every individual note in the chord, which is why, if you specify the interval (eg. shift-i t M3) the result is correct, but if you only specify a scale degree (shift-i t 3) the result will be less predictable.
eg. (In C major) a Dm7 (d,f,a,c) → shift-i tM3 → F#m7 (f#,a,c#,e)
Well, even if the suggested methods work well (and are logical and consistent), it would be nice if the Respell Using Note Name Above/Below commands would be implemented to respell Chord Symbols as well (@dspreadbury).