The "Second Call" service also allows you to switch to another call when you are already on the line.
How does it work?
If a second person tries to call you while you are already on line with someone else, you will still be able to answer the second call. If you do, your first caller will automatically be put on hold. You can then switch between both conversations.
Normally, this service should be automatically activated on your smartphone. Not the case? Then you can easily activate it from the settings of your device.
Do you have an iPhone? Go to the 'Settings' > 'Phone' > 'Call Waiting' > Activate or deactivate the function.
Do you have an Android device?
Good to know: Do you have 2 SIM cards in you handset? You can choose wether to activate the function for each SIM card.