This guide outlines the procedure for adjusting the audio input/output devices on the Communicator app.
Open the Preferences panel by clicking the three dots on the right side of the blue bar on your Communicator app:
Go to the Audio section of the Preferences panel.
From there adjust the three drop downs for the microphone, speaker, and ringing device to the desired device:
Once you have adjusted the device accordingly click the OK button at the bottom of the panel to save the new settings.