An alias is not a property of a key. Therefore, an alias can be mapped to and unmapped from an existing key without changing the properties of the key.
An alias name can contain only alphanumeric characters, forward slashes (/), underscores (_), and dashes (-). An alias must start with the word "alias" followed by a forward slash (alias/). An alias that begins with "aws" after the forward slash (alias/aws...) is reserved by Amazon Web Services (AWS).
The alias and the key it is mapped to must be in the same AWS account and the same region.