Approach :

1) Create a activity in the corresponding class Eg: - Work Class

2) Have 4 parameters Eg: CaseID, InsKey [ Case key ] , AssignInsKey [assignment key], OperatorID 

3) Passing the case ID to get the Key for the work class of the case ,using obj browse.

4) Using the results from the step 3 , set the key to param.

5) Open the case , by passing param mentioned in step 4.

6) Get the list of assignment from the workbasket class, passing key to obj browse

7) Loop through the pagelist populated from step 6 and use pxTransferAssignment activity to transfer to WL.

8) refresh and lock/ obj save.

Thanks

Chandan U