Divisi Basses

I am writing a large orchestral work and want to import a flow into it as i orchestrated part of it separately in a different project. The problem is in the main project my basses are ‘Double Basses’ whereas in the project i want to import they are ‘Contrabasses’. When i import the flow i merge instruments where possible. I am unable to change the contrabasses in the project to Double Basses. So instead i decided to import them as contrabasses and then past the music into the double basses already there and then delete the section players 'Contrabasses. However, when i try and copy paste the contrabass part into the Double Basses part i come across a problem.
The Double Basses as you can see from the file appear to be in unison whereas the contrabasses have a divisi section i want to paste into the double basses. However when i go to create a divisi section in the double basses it just says ‘restore unison’ despite there being no extra divisi stave. ( I’ve tried turning all condensing off as well.) I would be grateful if anyone has any advice on this and efficient ways of importing large orchestral flows in general because it’s something that i just cannot get to work correctly.
Many thanks.
Forum save 1.dorico.zip (760 KB)

What happens when you try? Are you using “Change Instrument” in Setup mode?

Or at least, just change the name?
Screenshot 8.png

It looks like the option to change instrument ist not available once your instrument has a divisi.
In your file, to copy the content of the Contrabass to the Double Bass, you should copy the divisi (signpost) first. Select the divisi signpost and alt-click at the same ryhtmic position in the Double Bass staff. Then select the content of the Contrabass (select to the end of flow is ideal here) and copy to the Double Bass. Delete the Contrabass.

Thanks rafaelv this works.