Process validation (Prospective validation)

I have read an article or guidelines of process validation that “Prospective process validation is validation conducted prior to the distribution of either a new product or a product made under a revised manufacturing process, where the revisions may affect the product’s characteristics.”
So in that defination I don’t understand the line " product made under a revised manufacturing process" because if we are changes in process than we have to perform revalidation not prospective validation.

So which validation we have to performed for revised manufacturing process?

If I understood your question correctly, there is a change in an already validated manufacturing process, and needs to be revalidated.

This re-validation, must be done as prospective validation, which means that PV lots cannot be releasede until the validation is completed and approved. If there is an actual rationale for Concurrent validation, then that must be justified in the change control and meet specific requirements for this approach.

A quick description betweem prospective, concurrent and retrospective validation approaches can be seen here: Process Validation

You can read more about requirements for process validation approach in FDA’s guidance for industry: Process Validation and EU GMP’s Annex 15 Qualification and Validation