Mengchu Cai, et al, show us how to change collation with Redshift:
Amazon Redshift is a fast, fully managed, cloud-native data warehouse. Tens of thousands of customers have successfully migrated their workloads to Amazon Redshift. We hear from customers that they need case-insensitive collation for strings in Amazon Redshift in order to maintain the same functionality and meet their performance goals when they migrate their existing workloads from legacy, on-premises data warehouses like Teradata, Oracle, or IBM. With that goal in mind, AWS provides an option to create case-insensitive and case-sensitive collation.
In this post, we discuss how to use case-insensitive collation and how to override the default collation. Also, we specifically explain the process to migrate your existing Teradata database using the native Amazon Redshift collation capability.
Specifically, it appears that they have two collations exposed: one which is case-sensitive and the other which is case-insensitive.