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There are two post functions that users can add to any transition as seen in the figure. The first post function (Assign By Rule) does that, assigning users according to assignment rules(Global Rules and Project Rules) which matches with the appropriate issue that is defined before. The second post function (Assign To Alternate User) assigns to the alternate user when a user is unavailable.
Info Panel
In the Setting of Time Off Management & Auto Assignment on the admin page, you can select to display or not to display the Assignee Unavailability panel on the issue if there is no data.
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If you check the option, the info panel will be seen as below. By default, the info panel is not seen at all, if there isn’t any data.
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