Hi,
Assuming you are replacing the certificate on a view connection server? Is the certificate currently the default self signed VMware certificate or has there been one generated from a third party or local CA?
Depending on your version, it might be worth looking through the documentation from VMware here. Specifically relating to your question, you will be able to renew your certificate using the same key if that is how you wish to proceed without renewing the private key. If you wish to generate a brand new private key and certificate then you will have to perform a whole new certificate generation request.
Happy to help.
Regards,
Ryan