Why did Apple xr set up the call and the main card appeared again?

1, unlock the screen, find the settings to enter, and click cellular mobile network; 2. Then click the first card under the cellular phone number; 3. Enter the number card setting interface, and click the cellular mobile label to enter; 4. At this time, you will see the primary and secondary card labels, and select the secondary number to return; 5. Return to the mobile cellular network and click to enter the second card. Similarly, you can also set it to the main number and then return. 6. The primary and secondary numbers have been set successfully. You can open the control center, and the signal has been automatically marked in front.

IPhoneXR is a mobile phone product released by Apple at 0 1: 00 am on September 18, Beijing time (September 12, California time 10: 00 am, USA) at Steve Jobs Theater in Apple Park in San Jose.