An arrangement of an existing musical work usually requires the prior consent of the author or the holder of the arrangement right. This is because the editing right is regarded as the rule of “encroachment” on the existing copyright. This also serves to protect the author.
The edited musical work in turn exhibits copyright quality. For example, the edited work may not be further edited without the consent of the (authorised) arranger.
However, there is no editing if a musical work is merely quoted or described in general terms.
In case of doubt, the author must be asked for permission before editing.