Hey there! While there isn't that exact functionality, AutoSSL has an option that will help ensure you always have a certificate in place. In WHM >> Manage AutoSSL under the "Options" tab you'll see this:
"Allow AutoSSL to replace invalid or expiring non-AutoSSL certificates."
which has this description:
"This option will allow AutoSSL to replace certificates that the AutoSSL system did not issue. When you enable this option, AutoSSL will install certificates that replace users’ CA-issued certificates if they are invalid or expire within 3 days."
That will let AutoSSL attempt to renew non-AutoSSL certificates. If the process fails for some reason, the old certificate will stay in place. If it works, it will just be replaced with the new AutoSSL certificate. This way you don't have a period where there is a gap while you delete the old certificate.