Reduce expiry dates for existing Client Secrets for App Registrations & Service Principals?

Hello!

In the past, our organization has generated client secrets for SPNs with a secret expiry date of 10 years in the future. With a policy update, this is no longer allowed. Instead of forcing a large number of customers to replace their secrets right now, is there a way to reduce the expiry date of the existing secrets to conform to the new limit?

On a related note, when you generate a new client secret for a Service Principal which already has exsting (non-expired) secrets, are those other secrets in any way invalidated or their validity shortened? There's a rumor that those get set to 7 days grace period regardless of their previous expiry date, but I couldn't find any mention of this in any of the official Azure documentation.

Thank you!