Huawei Honor 3C H30-U10 User Guide - Manual (Page 24)

Calls
20
Answering or rejecting a call
When a call comes in, you can press the volume button to mute the
ringtone.
•
Drag right to answer the call.
•
Drag left to reject the call.
•
Drag up to reject the call and send the caller a message.
On the dialer screen, touch > Settings > Reject calls with SMS to edit
the message that will be sent.