From the My Visitor page, search for the visitor you want to share a pass with, or add a new visitor wether permanent or temporary.
Tap their name to open their details.
Towards the bottom, click Share QR Pass and then chose the way you would like to send the pass.
Passes for One-Time visitors cannot be reused
Permanent visitors can reuse the same pass
Note: you may need to sign out of the app to activate the QR function
Watch the how-to video: