Disable the Consultative Transfer option in System Options > Agent Preferences > Call Handling.

Use Direct Transfer to forward an impending call to the third party without announcing the call transfer.
To transfer the call to your supervisor, in the Work List window, click . For steps, see Calling Supervisors from Contact List.
To transfer the call using the SpeedDial list, in the Work List window, click . For steps, see Making a call using SpeedDial.
To transfer the call to an agent in the contact list, in the Work List window, click . For steps, see Making a call using Contact List.
To transfer the call to an agent using the text input field, in the Work List window, click . For steps, see Making a call using the text input field.
The system transfers the active call to the selected contact directly. If you have set the work completion option to the Allow Follow-Up mode, the call moves the work item into the follow up state when the transfer is complete. For details, see Completing the work.