How to copy content from staff 1 to staff 2 without deleting the content of staff 2?
What about selecting both staves, copy, Edit > Passte Special > Reduce (into the second stave)?
Edit: you really haven’t given us enough information to answer the question definitively.
Is the existing material homophonic? Do you want the content of voice 1 in the same voice in staff 2? Are there tuplets involved in either stave? All of these have consequences.
Broadly speaking, there are excellent filters available for filtering individual voices and notes in chords. If you want to paste extra notes into chords then turn on chord mode (hit Q) before pasting. Bear in mind you can filter and then paste into a specific voice. Fully investigate the arranging tools that make up the Paste Special submenu.
Thanks but “Reduce” is greyed out.
At the moment I am just trying to merge the content of two homophone voices
It’s a paste feature. You have to cut or copy first. You then need to select where you want to paste to (in this case, the second stave). You might benefit from reading page 29 of the Version History, here: http://download.steinberg.net/automated_updates/sda_downloads/Dorico-2-2.0.0-44b04f1e-3f76-4fad-a938-d35e5f7dbd19/Dorico_2.0_Version_History.pdf
You should be able to cut the material of the second voice and paste it into the other voice with chord input active.
That was the missing link!
Thanks for this