Allow to set the "sender" and "from" properties of a message
When composing a message, let the add-in set the "sender" and "from" properties.
Remark: So far it is only able to read them.
This is a feature that could be dangerous, and probably we will never ship.
Can you please add more detail to your request? What’s the scenario you are trying to accomplish.
Markus Lauff commented
When using Outlook, the user can (already) set his from/sender address to which he is allowed to send on behalf. This feature is for example being used with shared mailboxes.
The request is about doing the same from the script.