[#53420683] Updated the "Act on behalf of another user" page on the knowledge base.

![1](https://f.cloud.github.com/assets/2251119/1515549/92c798ce-4b04-11e3-88ae-66112462b7fc.png)

![2](https://f.cloud.github.com/assets/2251119/1515550/967ae4a8-4b04-11e3-90c9-e14f74f893bc.png)

![3](https://f.cloud.github.com/assets/2251119/1515552/98e5d748-4b04-11e3-8f75-8ea696fff021.png)