code: public MergeRequest unapproveMergeRequest(Object projectIdOrPath, Integer mergeRequestIid) throws GitLabApiException {
  
          if (mergeRequestIid == null) {
              throw new RuntimeException("mergeRequestIid cannot be null");
          }
  
          Response response = post(Response.Status.OK, (Form)null, "projects", getProjectIdOrPath(projectIdOrPath), "merge_requests", mergeRequestIid, "unapprove");
          return (response.readEntity(MergeRequest.class));
      }
docs: Unapprove a merge request.
  
  Note: This API endpoint is only available on 8.9 EE and above.
  
  <pre><code>GitLab Endpoint: POST /projects/:id/merge_requests/:merge_request_iid/unapprove</code></pre>
  
  @param projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance
  @param mergeRequestIid the internal ID of the merge request
  @return a MergeRequest instance with approval information included
  @throws GitLabApiException if any exception occurs