Adding to Caitlan's comment...
The way Screen Share would work to achieve what you are asking:
1. The agent is talking to a caller, and the caller wants to ask a question about something they are seeing on their computer
2. The agent tells the caller to browse to a web site which has the screen share components for PureCloud embedded.
3. The agent starts a screen share session, which gives the agent a key.
4. The agent then tells the caller to click on the web site control (button, usually) to start screen share, and gives the caller the key to enter. That connects the caller's end of screen share with the agent's session.
Once they are connected, the agent will be able to see the caller's computer screen.
As Caitlan said, it requires some web development to set up the web site with screen share capability. On the agent side, the ability to start screen share is controlled by permissions, and will be available in the agent's client interface.
All available soon!