diff --git a/api-documentation.md b/api-documentation.md
index 01df022..1c66bc8 100644
--- a/api-documentation.md
+++ b/api-documentation.md
@@ -559,7 +559,7 @@ A json object for the deleted participant with `message`.
 | :------------ | :-------- | :-------------------------- |
 | id            | int       | primary key, auto-increment |
 | meeting_id    | varchar   | foreign key, required       |
-| possible_date | date      | required                    |
+| possible_date | string    | required                    |
 | created_at    | datetime  | generated by database       |
 | updated_at    | datetime  | generated by database       |