code: public boolean respondToReinvite(SipTransaction siptrans, int statusCode, String reasonPhrase,
        int expires, String newContact, String displayName, String body, String contentType,
        String contentSubType) {
      return respondToReinvite(siptrans, statusCode, reasonPhrase, expires, newContact, displayName,
          body, contentType, contentSubType, null, null);
    }
docs: This method sends a basic response to a previously received RE-INVITE request. The response is
  constructed based on the parameters passed in. Call this method after waitForReinvite() returns
  non-null. Call this method multiple times to send multiple responses to the received RE-INVITE.
  
  @param siptrans This is the object that was returned by method waitForReinvite(). It identifies
  a specific RE-INVITE transaction.
  @param statusCode The status code of the response to send (may use SipResponse constants).
  @param reasonPhrase If not null, the reason phrase to send.
  @param expires If not -1, an expiration time is added to the response. This parameter indicates
  the duration the message is valid, in seconds.
  @param newContact An URI string (ex: sip:bob@192.0.2.4:5093) for updating the remote target URI
  kept by the far end (target refresh), or null to not change that information.
  @param displayName Display name to set in the contact header sent to the far end if newContact
  is not null.
  @param body A String to be used as the body of the message, for changing the media session. Use
  null for no body bytes.
  @param contentType The body content type (ie, 'application' part of 'application/sdp'),
  required if there is to be any content (even if body bytes length 0). Use null for no
  message content.
  @param contentSubType The body content sub-type (ie, 'sdp' part of 'application/sdp'), required
  if there is to be any content (even if body bytes length 0). Use null for no message
  content.
  @return true if the response was successfully sent, false otherwise.