Query Tuning

Hello All,

I am trying to tune a query that takes 4 minutes to execute.

SELECT REQUEST_ID,
               INSTANCE_ID,
               GCI,
               REGIONS,
               JURISDICTIONS,
               APPROVER_LOB,
               ENTITY_NAME,
               DETAILS,
               (SELECT INITCAP (LAST_NAME) || ', ' || INITCAP (FIRST_NAME)
                  FROM LEO.USERS
                 WHERE NB_ID = REQUEST_NBK)
                  AS INITIATED_BY,
               TO_CHAR (DATE_SUBMITTED, 'MM/DD/yy HH:MI AM') DATE_SUBMITTED,
               PENDING_WITH,
               REQUEST_TYPE,
               ACTION_REQUIRED,
               ASSIGNED_TO,
               ROW_NUMBER () OVER (ORDER BY DATE_SUBMITTED DESC) RN
          FROM ALBPM.DASHBOARD_CLIENTDETAILS
         WHERE ( (UPPER (PENDING_WITH) IN (SELECT DISTINCT UPPER (ROLE_NAME)
                                             FROM LEO.USERS_ROLE_INFO_VW
                                            WHERE NB_ID = UPPER ('NBKBMU4'))