If you are configured as a delegate (alternate/backup) to a Signing Official (e.g.: Chair, Dean, Provost, etc.), your Action List will have a pick-list of choices to select from. Note that Action Lists always open to your OWN list which may be empty/blank or have items listed in it like this example.
Select (pull-down) the individual you are delegate for to view their Action List.
Note that items in the Signing Official's Action List display the name of the official you are delegate for:
Click on the ID (linked number), just as you would in your own Action List, to review and authorize the proposal.