diff --git a/specification/components/stu3/schemas/endpoints/a031-change-shortlist.yaml b/specification/components/stu3/schemas/endpoints/a031-change-shortlist.yaml
index 9f990831e..7ce1db28a 100644
--- a/specification/components/stu3/schemas/endpoints/a031-change-shortlist.yaml
+++ b/specification/components/stu3/schemas/endpoints/a031-change-shortlist.yaml
@@ -37,11 +37,15 @@ description: |
   In order to use this endpoint you must be an authenticated e-RS user and use one of the following e-RS roles:
   - `REFERRING_CLINICIAN`
   - `REFERRING_CLINICIAN_ADMIN`
+  - `SERVICE_PROVIDER_CLINICIAN`
+  - `SERVICE_PROVIDER_CLINICIAN_ADMIN`
 
   You need to use the `Unique Booking Reference Number` (UBRN) of a referral request in order to use this endpoint.
 
   You need to have found services that meet the referral needs of a patient using [[HYPERLINK_A010]].
-
+  
+  Where a `SERVICE_PROVIDER_CLINICIAN_ADMIN` (SPCA) is acting on behalf of a `SERVICE_PROVIDER_CLINICIAN` (SPC), the 'on behalf of' user ID must be that of an appropriate SPC. You can use endpoint [[HYPERLINK_A040]] to determine which e-RS users a `SERVICE_PROVIDER_CLINICIAN_ADMIN` is allowed to work 'on-behalf-of'.
+  
   ## Use case
   As an authenticated user
 
@@ -59,6 +63,8 @@ description: |
   For the referral to be processed by the service provider, you must ensure appropriate referral letter information has been added to the referral. You can add/manage referrer letter information by using [[HYPERLINK_A012]].
 
   You can check to see what referral letter information has already been added to a referral by using [[HYPERLINK_A005]], [[HYPERLINK_A007]], and [[HYPERLINK_A006]] endpoints where necessary.
+  
+  When making a request as a `SERVICE_PROVIDER_CLINICIAN_ADMIN` (SPCA) use endpoint [[HYPERLINK_A040]] to determine which `SERVICE_PROVIDER_CLINICIAN` (SPC), the SPCA is allowed to act 'on-behalf-of'.
 
   ## Known Issues
   
@@ -75,6 +81,7 @@ parameters:
   - $ref: '../headers/request/BusinessFunction.yaml'
   - $ref: '../headers/request/CorrelationID.yaml'
   - $ref: '../headers/request/IfMatch.yaml'
+  - $ref: '../headers/request/OnBehalfOfUserID.yaml'
   - $ref: '../pathParameters/Ubrn.yaml'
 requestBody:
   required: true
diff --git a/specification/components/stu3/schemas/responses/changeShortlist/422Response.yaml b/specification/components/stu3/schemas/responses/changeShortlist/422Response.yaml
index 0dbbebdaa..8fdd6ffaa 100644
--- a/specification/components/stu3/schemas/responses/changeShortlist/422Response.yaml
+++ b/specification/components/stu3/schemas/responses/changeShortlist/422Response.yaml
@@ -12,6 +12,7 @@ description: |
   | INVALID_CODE                       | The input provided for a field is not one of the defined legal values. |
   | UNEXPECTED_FIELD                   | A field is provided that is not expected as part of the request. E.g. a field is mis-spelt, was defined on a previous version of the endpoint but has subsequently been removed. |
   | INVALID_FHIR_STRUCTURE             | The FHIR data structure in the message body does not match the expected structure (e.g. an array is present for a value when no array is expected). |
+  | INVALID_STATE                      | Indicates that the referenced item is not in the correct state for the request to be processed (e.g. a service of the wrong type). |
   | ORGANISATION_IS_CLOSED             | The organisation supplied corresponds to an organisation that is closed. |
   | ORGANISATION_NOT_APPROPRIATE       | The organisation supplied corresponds to an organisation that is not valid for the given request. |
   | DUPLICATE_SERVICE                  | Unique service value expected. |