Add dedicated section for cert replacement

Author: RebeccaTamachiro

src/content/docs/ssl/reference/certificate-statuses.mdx

@@ -9,7 +9,7 @@ description: Understand certificate statuses in Cloudflare SSL/TLS, including st
 Certificates statuses show which stage of the issuance process each certificate is in.
 ## New certificates
 
-When you order a new certificate, either an [edge certificate](/ssl/edge-certificates/) or a certificate used for a [custom hostname](/cloudflare-for-platforms/cloudflare-for-saas/security/certificate-management/), its status will move through various stages as it progresses to Cloudflare’s global network:
+When you order a new certificate, either an [edge certificate](/ssl/edge-certificates/) or a certificate used for a [custom hostname](/cloudflare-for-platforms/cloudflare-for-saas/security/certificate-management/), its status will move through various stages as it progresses to Cloudflare's global network:
 
 1. Initializing
 2. Pending Validation
@@ -21,6 +21,12 @@ Once you issue a certificate, it should be in **Pending Validation**, but change
 
 If you deactivate a certificate, it will become a **Deactivating** and then an **Inactive** status.
 
+### Certificate replacement
+
+When replacing a certificate, you may note a **Pending Cleanup** status. Old certificates are not deleted until the replacement has been successfully issued. This helps ensure TLS will not break for the hostname while the certificate is being replaced.
+
+When the new certificate is successfully issued and activated, the status for the old certificate will transition from **Pending Cleanup** and the certificate will be deleted.
+
 ## Custom certificates
 
 If you are using a [custom certificate](/ssl/edge-certificates/custom-certificates/) and your [zone status](/dns/zone-setups/reference/domain-status/) is **Pending** or **Moved**, your certificate may have a status of **Holding Deployment**.