Question posted in 
Is there anyway to change existing bucket that has standard storage class into Express One Zone?
I searched a lot and couldn’t find a way to convert it
I tried with command or AWSL CLI command. I made sure that I was in the last version.
I noticed that this type does not exist when I perform the command to list all storage classes.
2
Answers
The short answer would be, no you cannot switch between standard class and express one zone.
Buckets can be either General purpose (original S3 buckets that support the storage classes that we are all used to) or Directory buckets (using the S3 Express One Zone storage class). These 2 types of buckets are separated and you cannot switch between them. There are some differences in using buckets that simply do not allow the change. Among other things, naming rules for buckets are different for the general purpose buckets and directory buckets.
The Bucket type can be:
The Bucket type is selected when the bucket is created and cannot be changed.
The Express One Zone storage class requires a Bucket Type of Directory.
Therefore, it is not possible to change the Storage Class of objects to/from Express One Zone because it would also require a change of Bucket type, which is not permitted.