title: Nodejs service to query dynamoDb on different aws account
body: <p>I have a nodejs service running on an EC2 in account A.
  In addition, I have dynamoDB table in account B.</p>
  <p>I want to query the table in account B, but by default, the package only gets tableName and query the current account.</p>
  <p>Is it possible to add something like accountId to the AWS Config?</p>
  <pre><code>        dynamo.AWS.config.update({region: process.env.DYNAMO_DB_REGION});
  </code></pre>