Simplest certbot command to expand a certificate

Question

In nowadays (...2017), what the simplest and secure certbot command to expand an existing certificate?

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NOTES:

• This question/answer is not about nowadays, --expand is not in use, etc.

Answer 1

See this official about Re-creating and Updating Existing Certificates

Answer 2

So far, 2017, version 0.12, no simple way. The procedure is to do all certificate.... The command is simple,

 certbot --cert-name xxxx.com.family -d xxxx.com -d xxxx.org -d xxxx2.org

There are a Wishlist with it, at certbot/issues/4352.