2.1. Incorrect DHE Share

RFC 8446

If the client has not provided a sufficient "key_share" extension
(e.g., it includes only DHE or ECDHE groups unacceptable to or
unsupported by the server), the server corrects the mismatch with a
HelloRetryRequest and the client needs to restart the handshake with
an appropriate "key_share" extension, as shown in Figure 2.  If no
common cryptographic parameters can be negotiated, the server MUST
abort the handshake with an appropriate alert.

      Client                                               Server

      ClientHello
      + key_share             -------->
                                                HelloRetryRequest
                              <--------               + key_share
      ClientHello
      + key_share             -------->
                                                      ServerHello
                                                      + key_share
                                             {EncryptedExtensions}
                                             {CertificateRequest*}
                                                   {Certificate*}
                                             {CertificateVerify*}
                                                      {Finished}
                              <--------       [Application Data*]
      {Certificate*}
      {CertificateVerify*}
      {Finished}              -------->
      [Application Data]      <------->        [Application Data]

            Figure 2: Message Flow for a Full Handshake with
                        Mismatched Parameters

Note: The handshake transcript incorporates the initial
ClientHello/HelloRetryRequest exchange; it is not reset with the
new ClientHello.

TLS also allows several optimized variants of the basic handshake, as
described in the following sections.

The HelloRetryRequest mentioned in section 2.1. of the draft is actually a special ServerHello message which is defined in detail in section 4.1.3. of the RFC. You can find details of the modelled HelloRetryRequest here.