Huawei
Reject an Incoming Call auf Huawei
An incoming call at the wrong moment needs a fast, silent response. On Huawei phones this is handled by the call screen itself, not by a setting buried in the dialer app.
When a call comes in, a circular icon and a red phone icon appear on the display. Moving the circle onto the red icon tells the system to end the call attempt right away, before you ever unlock the phone.
Tap and hold the circle icon ➔ Drag the circle on the red phone icon ➔ Release the circle icon. The call disappears from the screen the moment you release it over the red icon.
Depending on your carrier, the caller either hears a busy tone, gets forwarded to voicemail, or simply sees the call as unanswered. Rejecting a call this way does not block the number: the same caller can dial again immediately.
If the ringtone is the actual problem rather than the call itself, pressing a volume button mutes the sound without ending the call, which can be the better choice if you still plan to call back within seconds.