diff --git a/source/_integrations/conversation.markdown b/source/_integrations/conversation.markdown
index 86cc5fc7f3a..3eafecb231e 100644
--- a/source/_integrations/conversation.markdown
+++ b/source/_integrations/conversation.markdown
@@ -166,6 +166,7 @@ Send a message to a conversation agent for processing.
 | `text`                 | no       | Transcribed text input                                                                                                    |
 | `language`             | yes      | Language of the text                                                                                                      |
 | `agent_id`             | yes      | ID of conversation agent. The conversation agent is the brains of the assistant. It processes the incoming text commands. |
+| `conversation_id`      | yes      | ID of a new or previous conversation. Will continue an old conversation or start a new one.                               |
 
 This service is able to return [response data](/docs/scripts/service-calls/#use-templates-to-handle-response-data). The response is the same response as for the
 [`/api/conversation/process` API](https://developers.home-assistant.io/docs/intent_conversation_api#conversation-response).