American Express has had lounges under various names, but it appears they are trying to consolidate them all under the Centurion brand.
Amex has today informed its cardholders in Australia that Melbourne and Sydney lounges are closed November 21 – December 21, 2022, while conversion to Centurion designation is performed.
You can access the Amex page for Australian lounges here.
Email from American Express:
It makes sense for American Express to have a global Centurion branding for its lounges.
The Sydney and Melbourne lounges are only closed for 10 days, so there cannot be any significant remodeling done over such a short period.