Sorry, I did not understand the question.
Could you explain ?

I've create a new profil, I want for this profil, only access for modify the traitement of project expense, to change the status.

If i just put this profil with access to data / project expense : Manager+
this profil can show all of project expense, create new but cannot change the status of already project expense exist.

I hope that you understand my pb ...

Most possibly because your new profile has no right on workflow management used for project expense type.

You can test on Demo with user Accountant (profile Manager+ on project expense) : works as expected.