Team, Is it possible to refactor and migrate a application module alo

Could you explain your use case in more detail? Are you talking about one application/process model?

Refactoring and Migrating and two totally different operations. Refactoring is done at the process design level and migration is done at the data entity level.
In short, Appian 'instances' can be migrated from one version to another. You need to read the release doc and migration doc on Forum-->Software that has clear instructions. As long as you have not modified the base product files, it should work seamlessly.
With regards to refactoring, this is done at the application / process level. Based on what you want to refactor and how you want the refactored changes to apply (either to new instances or existing instances), you work out an approach accordingly.
Hope this is clear.

Thanks for your response. I explain my question in details. Consider I have a cluster of applications in 6.6.1. If i need to migrate a portion of application, with some of its intances along with data to a higher version say 7.4, is it possible? If so, how can we achieve the same?