Hello @R.Luzi, 

Once an allocation period has been set, if your accountant generates accountant entries linked to this invoice, you will not be able to change it later 

If it’s not, you can change as you want.

If you want to change some data, you can ask directly your accountant by tag him in a comment for example : 

Could we change the behavior so it’s still possible to fix the invoices information without having to ask the accountant?

Hello @Olivier Tassinari, for that I recommend you to contact the support team, by clicking on the button “Aide & Support > Nous contacter”