To Enlarge/Expand the conversation
sounds more about expanding the focus of the conversation, not the fact that we want to discuss this issue with other people.
To Enlarge/Expand the conversation
sounds more about expanding the focus of the conversation, not the fact that we want to discuss this issue with other people.
Expanding the conversation 1 2 is perfectly acceptable and often used to describe the act of broadening the reach of your discussion to more and more people -- not transforming the focus of the conversation, as you assumed it to be.
Enlarge the conversation, on the other hand, is not idiomatic and should not be used in any circumstances.