code: public OAuth2Request narrowScope(Set<String> scope) {
  		OAuth2Request request = new OAuth2Request(getRequestParameters(), getClientId(), authorities, approved, scope,
  				resourceIds, redirectUri, responseTypes, extensions);
  		request.refresh = this.refresh;
  		return request;
  	}
docs: Update the scope and create a new request. All the other properties are the same (including the request
  parameters).
  
  @param scope the new scope
  @return a new request with the narrowed scope