Rehost

• Move as-is while minimizing change

Replatform

• Involve updates solution components(OS, middleware, DBs)

Refactor

• Big change to solution architecture and codebase

Rearchitect

• Rebuild App on a cloud-native app stack
• Change the way a piece of code works

Replace

• Retire old and dev new App from new requirements and technology
• Can involve SaaS solutions

Repurchase

• drop and shop: decommissioning the application and replacing it with a cloud-based version
• typically on the Cloud Marketplace.
• Effectively, this is a licensing change—instead of using a traditional on-premise license, you can start using the same application as a cloud service.

Retain

• "In many cases, during a migration project you can identify applications that are redundant or to be consolidated"
• Shut the redundant down can represent a cost saving.