In-Call Screen Layout And Options - Samsung Galaxy S6 edge+ User Manual

The ringtone or vibration will stop and call will be sent directly to voicemail.
Reject a Call and Send a Text Message
You can reject an incoming call and automatically send a text message to the caller.
1. When a call arrives, drag Reject call with message up from the bottom of the screen.
2. Tap one of the messages to send it to the caller.
The selected message will be delivered to the caller.
You can edit existing reject messages or create new ones through the Call settings menu.
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From home, tap Apps
Call-reject messages and edit or create reject messages.

In-Call Screen Layout and Options

While you are on a call, you will see a number of onscreen options.
Phone App
> Settings > Applications > Phone > Call blocking >
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