Step 1: Go to the TMS URL: 

Step 2: Choose the correct account

Step 3: Click on the Extension Manager menu item.

Step 4: Click on the Extension sub-menu item.

Step 5: Select the correct extension.

Step 6: Click on the Agent tab at the top.

Step 7: Untick the box next to “Allow Call Transfer”

Step 8: Click “Apply” to save the configuration.