2 people editing the same PDF live in real-time

User A has uploaded a fillable PDF to Adobe Cloud Storage and shared it with User B. The option 'people can comment on file' is checked. I need both users to be able to edit the PDF simultaneously in real time, similar to how Google Docs functions. However, when User B open the file and clicks anywhere, it says "Shared files can't be modified. Create a copy and make changes to your copy." How can we enable real-time editing for both users on this PDF? Both users have paid Acrobat Pro subscriptions