You may not want your designer to send a proof directly to the client. Instead, you want the designer to create the proof and pass this on to an account manager to then check and send on to the client. This can be easily be done using the Adobe add-on.
Uploading a proof and assigning the account manager as the owner
In the Adobe add-on, click the create new proof icon (for a brand new proof), or upload new version icon (for a new version of a proof).
In the proof set-up screen, in the owners section click the plus icon to add an owner and type in the email address of the account manager.
The account manager will be notified that the proof can be found in their dashboard outbox where they can view the proof, and complete the setup by assigning a workflow.