You can run dzinfo --roles or dzinfo username --roles to see if the emergency_access role is available based on the start time for the role definition and the local time of the Linux or UNIX computer.
At the specified start time for the role assignment on the local computer, the user you assigned to the emergency_access role can type the following command:
dzdo su - root
The user is not prompted to provide the password and becomes the root user on the local computer until the specified role assignment end time. The one caveat to be aware of is that the user would continue to have root access after the specified end time if the shell session remains open continuously. If a user is still logged on after the time period has expired, you should check whether the user still requires root-level access. If the session has remained open but the user should no longer have root access, kill the session and log the user off.