# What are change types?
<a name="understanding-cts"></a>

Change type refers to the action that an AWS Managed Services (AMS) request for change (RFC) performs and encompasses the change action itself, and the type of change – manual vs automated. AMS has a large collection of change types not used by other Amazon web services. You use these change types when submitting a request for change (RFC) to deploy, or manage, or gain access to, resources.

**Topics**
+ [Automated and manual CTs](ug-automated-or-manual.md)
+ [CT approval requirements](constrained-unconstrained-ctis.md)
+ [Change type versions](ct-versions.md)
+ [Create change types](ct-creates.md)
+ [Update change types](ct-updates.md)
+ [Internal-only change types](ct-internals.md)
+ [Change type schemas](ct-schemas.md)
+ [Managing permissions for change types](ct-permissions.md)
+ [Redacting sensitive information from change types](ct-redaction.md)
+ [Finding a change type, using the query option](ug-find-ct-ex-section.md)