Android KitKat 4.4 provided the feature to set phone on vibrate while on Call Waiting. It is sometimes required by the users to be intimated of incoming call while he/she is using the phone either for call or some other activity.
During the usage of phone for call or any other activity, incoming call may become cumbersome, rather awkward, as it would cause the phone tone to ring. Here, Android comes forward to help with suggestion to enable the phone to vibrate while the user is on call waiting.
For the purpose, follow the instructions:
2: In the phone profile screen, tap the ‘Settings button’. It would open up a popup menu.