If you are a supervisor you should now be able to do this using the "Transfer Clients" feature in caseTRACK.
If you have permissions you should see this option on caseTRACK's main menu. Click it and you will see the Transfer Clients form.
Select the worker you are transferring from and then fill ou the rest of the form. Check the clients you wish to transfer and then click 'Transfer'.
Using the "Transfer Date", this feature ends the "Transfer From" worker assignment for all the selected clients and adds a new worker assignment record for the "Transfer To" worker.
Hopefully, this will save a lot of time for you going forward.