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TOM also has a JQL function called currentlyOffTime() which shows all the issues which are assigned to the absent user. On the right middle of the page, users are able to see the related information about the auto-assignment rules and by clicking “Assign to alternate assignee” it is possible to assign the issue till the end time is up!
In Project Rules section, users Users are able to add create assignment rules for each project separately.
In Global Rules section, users are able to reach the rules that is defined before from the Manage Apps section.
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For global rules management, you need to visit Global Rule Administration.
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By simply clicking the button called Assignment Rules (1)from the Admin page, users can easily reach the Global Assignment Rules configuration page. After that, just click the plus sign (2) on Create Global Rule button on the right top of the page and now you are ready to add a rule. You can also edit and delete the rules that you created before(3).
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While adding an assignment rule, users have to choose the rule name, assignee, assignment strategy and no assignment scenario. It is also possible to add JQL to the rule.
In Edit 
On the Update Assignment Rule page, there are some fields that you need to understand well which are,
“Project Scope” users can choose a single project, multiple projects, or global(global means ALL projects) for the rule that the user wants to implement it.
“Assignment Strategy” users can make a selection between Round Robin or Random. Let’s assume that we defined more than one assignee, round robin represents that, while implementing the rule assignees will be selected respectively instead of the absent user and random represents that, the user will be selected randomly between the assignees.
“No Assignment Scenario” consists of Alternate Assignee, Unassign and Do Not Reassign. Let’s assume there are two users(User A, User B) which who are considered as assignee assignees in the Add Assignment Rule screen and a random issue is assigned to User A. However User A is absent. On the other hand, User A had defined a rule for himself before from the admin section configuration page which is(If User A is absent, an alternate user will be User B). Then, that predefined rule will be working instead of this rule. Unassign means if the selected assignee is absent then the issues that are assigned to that user will be automatically set as unassignunassigned. Do Not Reassign means, nothing will change if the selected user is absent. The issues that are assigned to the absent user will remain the same and the assignee will still be the same user.
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There are two post functions that users can add to any transition as seen in the figure. First The first post function (Assign By Rule) does that, assign assigning users according to assignment rules(Global Rules and Project Rules) which matches with the appropriate issue that is defined before. Second The second post function (Assign To Alternate User) does that, assign assigns to the alternate user when a user is currently unavailable.
