Asus ZenUI Call Waiting, Holding & Conference Incoming Call (Android 8.1)
Asus Zenfone 4 Max ZenUI Android 8.1 merging two incoming calls into the conference.
00:00 Checking Android version
00:05 First incoming call
00:23 Answering
00:32 Putting on hold and answering the second line
00:36 Swapping calls
00:49 Merging into conference
01:08 Splitting and dropping calls.