This task requires permissions that are found in all default service security roles Defined sets of privileges.The security role assigned to a user determines which tasks the user can perform and which parts of the user interface the user can view. All users must be assigned at least one security role in order to access the system.. More information about specific permissions and performing this task while offline: Service Permissions
If additional actions are required for a resolved case, you can reactivate the case and modify it as needed. Microsoft Dynamics CRM reassigns the case to the customer service representative (CSR) who owned the case when it was closed. The benefit of reactivating the case is that you do not have to re-enter any data.To maintain a history of the status of a case, once the case has been reactivated, the case status changes to Active and the case resolution activity status changes to Canceled. When the case is resolved again, Microsoft Dynamics CRM creates a new case resolution activity.
In the Navigation Pane, click Service, and then click Cases.
In the View list, click My Resolved Cases or Resolved Cases.
In the list of cases, open the case that you want to reactivate.
In the Actions group, click Reactivate Case.
In the Reactivate the Selected Case dialog box, click OK.
Modify the information on the form or add any activities that you want.