code: public Offer update(Offer offer, boolean updateSubscriptions) {
          ParameterMap<String, String> params = new ParameterMap<String, String>();
          params.add("update_subscriptions", String.valueOf(updateSubscriptions));
          return RestfulUtils.update(OfferService.PATH, offer, params, true, Offer.class, super.httpClient);
      }
docs: Updates an offer.<br>
  <br>
  Following properties will be updated:<br>
  <ul>
  <li>name
  <li>amount
  <li>interval
  <li>currency
  </ul>
  
  @param offer               {@link Offer} with Id.
  @param updateSubscriptions When set to true, all associated subscriptions will be updated (except
  trial_period_days). When set to false, no subscriptions will be updated.
  @return the updated offer.