Unfortunately there isn't any way to reset its pin/pass.If it's preinstalled in your phone then only way is to factory reset phone.If it's downloaded from app store then you can uninstall it and then reinstall it.Pin will be reset after doing this.
There is a way , you can unlock your lock and mask app by this method: first you open lock and mask app then wihout taking a time click on change password and select ok in it. you have to done this consequently without taking a second.then you can unlock and can change your lock
