Resolution:
Here are the steps to activate delegation for a user/role.

1. Identify the user name and the role of the user to which you intend to delegate.
2. Run the following sql statement to identify the enterprise id.

    SELECT ID from ENTERPRISE where NAME= '&ltENTERPRISE NAME>'

3. Identify the ROLE ID of the user who intends to delegate workitems to another user.
SELECT ENT.ID OwnerID, PARENT.ID ParentID from ROLE PARENT, ENTERPRISE ENT  where ENT.NAME= '&ltENTERPRISE NAME>' and  PARENT.ENTERPRISEID = ENT.ID and  PARENT.NAME = '&ltROLE NAME OF THE USER>'
    Eg: Select ent.ID OwnerID, parent.id ParentID from Role parent, Enterprise ent  where ent.name= 'adm' and  parent.enterpriseid = ent.id and  parent.name = 'Admin'

4. Identify the ROLEID of the user to which a user wants to delegate workitems.

     SELECT ID FROM ROLE WHERE ENTERPRISEID = &ltENTERPRISE ID FROM STEP 2> AND NAME ='&ltROLE NAME OF THE USER TO WHICH WORKITEMS ARE TO BE DELEGATED>'
     Eg: SELECT * FROM ROLE WHERE ENTERPRISEID = 33100 AND NAME ='Catalog Editor'

5. Run the following insert sql statement:

    INSERT INTO RELATIONSHIP(OWNERID, PARENTID, CHILDID, TYPE,  MODDATE, PARENTVERSION, CHILDVERSION, QUANTITY,  
    MODMEMBERID, ACTIVE, CHILDOWNERID)  VALUES (&ltENTERPRISE ID FROM STEP 2>, &ltPARENT ID FROM STEP 3>, &ltROLE ID FROM STEP 4>, 10, SYSDATE, 1, 1, 0, 101, 'Y', -1 );
    COMMIT;

6. Now, you need to restart the server.
7. Login as 'Admin', go to User Accounts.
8. Modify the user for which delegation is to be activated.
9. Go to Delegation Profile, check "Activate Delegation", select "Start Date" and "End Date", select "Delegated Roles" and select the user to which workitems are to be delegated from "Available Users" and save the user profile.

How to delegate workitems assigned to a user?