The Master PIN can be changed on the Igloohome app under the Lock Info page. As this is done over Bluetooth, you have to be within Bluetooth range to change the Master PIN.

For Duration and Permanent PINs, the PIN can be changed to a 6 digit PIN of your (or your guest's) choice by entering *1 0 (#)<Current 8 Digit PIN> (#)<New 6 Digit PIN>(#)<New 6 Digit PIN>(#), following which , a long beep from the lock will indicate that the PIN has been successfully changed. The PIN change can only be done after the PIN has been entered on the lock at least once.