Merge pull request #25278 from microsoftgraph/jaalvarez-update-discardcheckout

Adds description of specific errors

Author: Lauragra

api-reference/beta/api/driveitem-discardcheckout.md

@@ -62,6 +62,12 @@ Don't supply a request body for this method.
 
 If successful, this action returns a `204 No Content` response code.
 
+### Error responses
+
+The request returns `400 Bad Request` if the file isn't checked out. Requests made with delegated access return `423 Locked` if another user has the file checked out. Requests made with application access can discard any checkout. 
+
+For more information about how errors are returned, see [Error responses][error-response].
+
 ## Examples
 
 ### Request
@@ -121,4 +127,4 @@ The following example shows the response.
 HTTP/1.1 204 No content
 ```
 
-
+[error-response]: /graph/errors