To ignore the call and reply with a text message, tap Decline with message.
Tap Send next to the desired response. Note: To create or edit text message replies, from the home screen, tap 'Phone' > press the Menu key > tap 'Call settings' > tap 'Decline with message' > tap the Add icon.
When receiving an incoming call, the Call icon will display in the notifications bar. The icon will also appear if you navigate away from the Phone screen while a call is active. Note: To learn about calling or using your device in other countries, visit the AT&T International Calling website.