There is a pretty simple solution using the completions API. You can just pad the conversation.
If you are using the chat completions, you can just pad it with fake conversation above it. Just remember, GPT is literally just a text predictor. Nothing really more than that. It’s easier to make prompts if you think of it that way. You aren’t trying to trick it into saying something, you are just trying to craft something that brings out a pattern that is more likely than other things.