You may want to grant access to the client to the order library if the requester needs to update a new version of the file or add reference material for the workers to be aware of. This is always possible even if you have previously started the work.
Access to the document library
The lower part of the order details, right below the document library will allow you to do so:
By default, clients have no access to the document library so any changes in the order will be handled by the manager in charge. He will responsible of giving access to client users to this area of their request, which ideally will express this need by using the message box in the order. This will allow your manager to have a record of all the history and be aware of document changes, do versioning at project level or exchange with the client about an alternative solution, if needed.