Click on the guest’s name, a window opens. Go under the 'Registration / Duplicates' tab.
You will have a new page showing all the guests with the same surname, on which you will need to select the wanted contact and click on 'Merge'.
Then, on the line 'Contact data', tick the column 'Contact selected in the previous step' and check the following lines and validate.
WARNING: this action is irreversible. If you have any doubt, contact Evenium support (+33 1 47 70 90 35 / [email protected]).