Samsung Galaxy S III User Manual page 97

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
 You will see a list of preset text messages.
2. Tap one of the messages to send it to the caller.
 The selected message will be delivered to the caller.
You can edit the reject messages through the Call settings menu. From the phone app, tap

Menu
messages.
Phone App
up from the bottom of the screen.
> Call Settings > Set up call reject messages and edit or create the reject
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