In trying to delete a network, my iphone doesn't show "Forget this network" only "Join this network." How do I get around that?

In trying to delete a network

Are you trying to delete a WiFi network that the iPhone is currently connected to?......or......are you trying to delete another WiFi network that the iPhone is not currently connected to?

You can only delete a network if the iPhone is currently connected to the network that you want to delete.

You cannot Forget a Network unless you are connected to the network. Once you are connected, you can tap on Forget, as that is the only time that choice will appear.