You can reset the password of an API user as follows.
1. Go to " Users".
2. Select " API access" in the top menu.
3. Select "More" and afterward "Reset Password" on the small padlock to the right of the user you want to change.
4. You will now be able to see the new code.
Get the API documentation here.
NB: Be aware of your GDPR compliance so nobody gets access to data they shouldn't.