The Web Protection > Deanonymization tab is only accessible if anonymization is activated (see Logging & Reporting > Reporting Settings > Anonymizing).
Here it is possible to abandon anonymization for specific users regarding web protection reports. Proceed as follows:
Enter both passwords.
Enter the first and the second password that have been provided to enable anonymization.
Add users to deanonymize.
To the Deanonymize users box add the usernames of those users you want to deanonymize.
Your settings will be saved.