Which option allows migration of Patterns from one instance to another?

The option that allows migration of Patterns from one instance to another is the Export Patterns UI Action. This functionality is designed specifically for the purpose of exporting existing patterns so that they can be imported into another instance. It packages the complete definition of the patterns, which makes it a seamless process to transfer complex configurations without the need for manual re-entry or potential errors.

Using the Export Patterns UI Action ensures that all the dependencies and relationships intrinsic to the patterns are preserved, providing a reliable means to migrate configurations between different environments, such as from development to production. This process enhances consistency across instances and simplifies the deployment of predefined patterns, making it a preferred choice for system administrators and developers managing Service Mapping in ServiceNow.

Other methods, like manual entry of patterns, while possible, are more prone to human error and time-consuming. Update sets are more general and typically used for broader kinds of configurations within ServiceNow, but do not target patterns specifically. XML Import can handle various data types but is not the streamlined method specifically intended for pattern migration like the Export Patterns UI Action. These aspects underline why the Export Patterns UI Action is the most effective option for this task.