How to cancel Unicom card HD?

Some netizens have encountered the problem of how p20 closes the high-definition call of Unicom card. The details of the question are as follows: p20 How to close the Unicom card HD call? I found that you collected some relevant solutions through the internet, hoping to help netizens who have had the same or similar problems. Details are as follows:

Solution 1:

VoLTE call function can be turned off in the following ways:

Method 1, setting >; Wireless and network > mobile network, and then turn off the VoLTE call switch.

Method 2: Contact Unicom customer service to close the SIM card VoLTE calling service.