Everyone knows that Dorico works ‘backwards’ compared to other software, i.e. you enter the parts for each instrument and then let the software condense them. Everyone? No, because most engravers enter a condensed score, above all in woodwinds and brass.
So when you receive a score like this, how do you revert to ‘Dorico mode’ so you can extract the parts as usual? What a pain…
Am I going to have to filter everything and copy and paste until my wrist cramps up? 
Erm? Nothing was attached, so we remain in the dark.
“like this” : that is a condensed orchestral score, with, for exemple two flutes on the same staff, two oboes, two clarinets, etc.
So, will I have to filter all these staves to redistribute the parts correctly?
I’m still having to guess…?
OK. So, if your received score has 2 voices, just move one voice to the other player.
But if your received score has chords, filter and move or explode them.
All very simple and quick to do.
Statements like these are quite nonsensical. You can’t possibly presume to speak for everyone or even “most engravers”. In Finale I worked exactly the other way around (i.e. entering parts seperately, always, and condensing afterwards) so Dorico for me felt extremely logical. It totally depends on personal preferences, workflow, types of projects, etc.
As for your question, without a concrete example, I’d say check the Explode function. Everyone uses it.
Tank you Janus for your reply.
The score display both : sometimes two voices, sometimes chords.
It will still take a considerable amount of time to complete in this 86 pages score. 
Ah… first time I hear that about Finale user.
I would be very interested to know your procedure, given that, as far as I know, Finale does not have an automatic condensation procedure, unlike Dorico.
It will still be quicker than manually re-entering…
(And please don’t insult me - I know you speak French, but you dropped the ‘h’ from ‘thank’)
(I think @ObiwanKenobi was just being a little facetious.)
From earlier encounters I disagree (sorry).
OUPS. The “H” indeed run away, but he has just been found in the cellar.
I Thank you very much again. 
The reason I did this is that 99% of the stuff I do is making arrangements. So I enter the source material and then I start moving things around in a new file. Doing this from a condensed score in Finale is a lot more steps because then you first have to uncondense (is that a word?) everything again. So I would enter every part on their own staff and when I was near the end of my process in my arrangement, I would make a copy of the Finale file and start condensing by using the implode function (or copying and pasting into different layers, depending in the material), and deleting staves. So in the end I always had two separate files, one for the score and one for the parts.
For that reason I was also used to doing everything related to layout/engraving at the very end. So both condensing and the separate Engrave mode felt tailor made when I switched to Dorico.
With shortcuts for the important functions, it can be faster than you might think. The main issue in cases like this (I imagine in yours?) is that manual condensing uses either one voice or two. It prevents the Explode feature to work properly.
Here’s what I would do:
Using the context menus makes this a bit cumbersome. But if you have shortcuts for Select Upstem/Downstem Voice, Select Top/Bottom Note, and also for Select/Deselect, it can be (relatively) fast:
It’s a tiny bit tricker if tuplets are involved but still doable!
Thank you very much Charles.
Comme on dit chez nous : « Y’a plus qu’à ».