What are variations you ask? Variations refer to a set of items that are the same product, but differ according to a consistent theme, for example size and colour. You can reference the following video and FAQ to help create and make updates to Variations: Variation Relationship FAQ
Variating ASINs:
The Variation Wizard allows you to add or update existing variation families and to create a new variation family. The Variation Wizard is located in Seller Central under Menu > Inventory > Manage Inventory > click Add Variation on the right-hand side. To create a new Variation Family, generate a category template with the Product Classifier. Then Upload your Inventory File and monitor your upload status.
Un-Variating ASINs:
If you accidentally Variate ASINs together, use the Split Product Detail Page Self Service Tool to remove the variation.