In Mekari Sign, you can change your PIN, which you can do for security reasons of your documents.

Here are the steps:

1. Go to Setting Menu page, click Account tab and select Digital certificate and Click "Change PIN".
   
   
2. Click “Change PIN”.
   
   
3. Enter your old PIN.
   
   
4. And then enter the new PIN you want to use and confirm your new PIN.