It would be handy to be able to right click a parent conversation and choose copy and then paste it into another characters conversation. Any child nodes attached to that conversation will also be copied.
Why not allow holding Lctrl key whilst doing this so you can select multiple parent conversations and copy them saving time if you want to copy over all or a few conversations.
Then after pasting them in, alter some of the text if needed to reflect characters style of delivery of lines etc.
Additionally having hotkeys to copy and paste would be a nice feature also not just for this but other areas where u can copy actions and restrictions, saves right clicking.