SPO USE ONLY
Yes up to a point. A delegate can be added to a signing official IF the proposal is at a stop PRIOR to that signing official. So, for example: A proposal is sent into routing and is presently at a Chair's stop (the Chair is reading it). A delegate can be added to the Dean, Cindy, the Provost, or Kevin at this point. But not the Chair.
If a proposal has routed to the stop of a signing official who is not able to sign and a delegate must be assigned, the proposal must be recalled, or a Super User Override action must be used. There is no way to add a delegate to a signing official once a proposal has arrived at their stop.