The created app lock password or PIN is independent of the unlock password of the screen lock and can be changed at any time, the
only condition is the current password or app lock PIN.

Android 10 | EMUI 10.0
Step 1:  Open the  Settings
Step 2:  Tap on  Security
Step 3:  Tap on  App Lock
Step 4:  Open the  Settings
Step 5:  Tap on  Password type  and follow the instructions on screen
  1. Open the Settings
  2. Tap on Security
  3. Tap on App Lock
  4. Open the Settings
  5. Tap on Password type and follow the instructions on screen

Huawei Instructions