Let's say you want to implement a workflow which should let the user select an agent they need help from based on the agents' location and other details like company department. Supposing that each employee has a user property with the country that they are based at; and that all employees are also grouped by their role in the team, this can be implemented very easily. After the end user selects the agent they want help from, an issue can be assigned to such employee.

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After the last screen executes, the assignee of the current issue will be set to the value selected in the User field - "josh" in this case.

See also

Example 2 - Logging work as another user