That's why I created a special dialogue just for you! Xan will eventually start a conversation, saying something like: "It is time. You cannot hide, though I wish you could". Then it's time to go to Spellhold.
As for dialogue files, they are tra-ified(= they're not in a dialogue structure anymore, it's just a list of lines with numbers), which means you'll have to read a Dialogue/O#XanJ.d file and English/O#XanJ.tra side by side and look up a number for every line. It's very annoying, and you'll see spoilers, naturally. But Notepad can help you there, absolutely. You can also download Infinity Explorer, open O#XanJ.d file in it and try to read it like a dialogue structure, though it's easy to get lost.