To change options for what happens when you are on a Teams call and a new call comes in, make changes to the options inside Settings as shown below.



From inside Teams:


Click Profile Name/Picture in the upper right.

Choose Manage Account

Choose Calls in the left column

Change the "When you're in a call and receive a call" option to what desired option is.


Options: 

  1. Let new calls ring me (rings through, if not answered - default is Voicemail)
  2. Play a busy signal (busy signal - not redirected to Voicemail)
  3. Redirect as if call is unanswered (see option above - default is Voicemail)