If you're able to get phone calls in Webex App, you get a visual and audible notification about another phone call while you're already on one. You can decide how you want to handle incoming calls by holding or ending your current call.
Webex App supports different types of calls that might affect the notifications you receive.
While on an active phone call, you can hold the call you're on and answer the incoming call.
If you get a phone call from someone who is using Webex App, you'll see this:
If you get a phone call from someone who doesn't use Webex App, you'll see this: