As the igloohome smart lock works offline, PIN codes cannot be de-activated via the app once they have been issued.
You will need to reset your lock via bluetooth (ie. be in close range of the lock) to ensure that the PIN code is no longer valid. Home owners are advised to be cautious when granting access to guests - it’s similar to entrusting someone with your key.
Alternatively, you may wish to share a Bluetooth Key. Bluetooth Keys can be revoked remotely.