How to make callers know I am on the phone with someone else?

[Windows Central Question]

I got a new Lumia for work. I get a lot of calls sometimes so often get people trying to call whilst I am on the phone with someone else. My issue is that they think I am ignoring my phone when I am busy. All I get on my end is an annoying beeping sound over my current call!

Is there a way I can stop this from happening so that they know I am busy?

Thanks.

 

[Laura Knotek]

If you disable call waiting, anyone who calls you when you are on another call will be taken straight to your voicemail.

 

[RumoredNow]

Open the Phone App > ellipses (. . .) > settings > toggle text reply to on > edit replies for a custom response such as "I'm on another call" or "I'm in a meeting"

When a second call comes in look at the screen and select your SMS response.