...
The plugin will try to reassign the user a different user than the absentee. This is configured by your administrator . Have a look at (ADMIN LINK(see Substitution Logic)
If configured by your administrator an e-mail will be sent to all user's in the Assign Issue event in the projects notification scheme to inform that an absent user was assigned.
If configured by your administrator a comment will be added to the issue to inform that an absent user was assigned.