diff --git a/api-ref/source/v3/attachments.inc b/api-ref/source/v3/attachments.inc
index fdc24630d17..06dbfcf44a4 100644
--- a/api-ref/source/v3/attachments.inc
+++ b/api-ref/source/v3/attachments.inc
@@ -106,7 +106,7 @@ Response Parameters
    - connection_info: connection_info
    - attached_at: attached_at
    - attach_mode: attach_mode
-   - instance: instance_uuid
+   - instance: instance_uuid_1
    - volume_id: volume_id_7
    - id: attachment_id_2
 
@@ -161,7 +161,7 @@ Response Parameters
    - connection_info: connection_info
    - attached_at: attached_at
    - attach_mode: attach_mode
-   - instance: instance_uuid
+   - instance: instance_uuid_1
    - volume_id: volume_id_7
    - id: attachment_id_2
 
@@ -212,7 +212,7 @@ Response Parameters
 .. rest_parameters:: parameters.yaml
 
    - status: status_9
-   - instance: instance_uuid
+   - instance: instance_uuid_1
    - volume_id: volume_id_7
    - id: attachment_id_2
 
@@ -274,7 +274,7 @@ Response Parameters
    - connection_info: connection_info
    - attached_at: attached_at
    - attach_mode: attach_mode
-   - instance: instance_uuid
+   - instance: instance_uuid_1
    - volume_id: volume_id_7
    - id: attachment_id_2
 
@@ -334,7 +334,7 @@ Response Parameters
    - connection_info: connection_info
    - attached_at: attached_at
    - attach_mode: attach_mode
-   - instance: instance_uuid
+   - instance: instance_uuid_1
    - volume_id: volume_id_7
    - id: attachment_id_2
 
diff --git a/api-ref/source/v3/parameters.yaml b/api-ref/source/v3/parameters.yaml
index 2aaa58ed1d6..b76ffb66aa8 100644
--- a/api-ref/source/v3/parameters.yaml
+++ b/api-ref/source/v3/parameters.yaml
@@ -441,7 +441,7 @@ attach_mode:
     The attach mode of attachment, read-only ('ro') or
     read-and-write ('rw'), default is 'rw'.
   in: body
-  required: false
+  required: true
   type: string
 attach_status:
   description: |
@@ -453,7 +453,7 @@ attached_at:
   description: |
     The time when attachment is attached.
   in: body
-  required: false
+  required: true
   type: string
 attachment:
   description: |
@@ -970,7 +970,7 @@ detached_at:
   description: |
     The time when attachment is detached.
   in: body
-  required: false
+  required: true
   type: string
 disabled:
   description: |