How can we Populate "Reporting To Email ID" & "User Additional Field" based on the User Selected Name?

How can we Populate "Reporting To Email ID" & "User Additional Field" based on the User Selected Name?

A particular Service Request template has 4 (four) additional fields "UserList", "Department name", "Company", and "Reporting To Email ID".

When users submit a ticket with this specific template, while typing the name (on the user name additional field which is "UserList"), it should populate the appropriate user names list within the ServiceDesk Plus. On selecting a user name, ServiceDesk Plus should also automatically populate the selected user's department on the department name field, Company which is User Additional Field & Selected User Reporting To Email Address.

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