I tend to ask for modifications on the 'latest' output.
If I need to roll back to a previous version, (2-3 outputs back) I either copy & paste and ask ChatGPT it to ignore all other versions and focus on the one I just pasted, or if I don't need my in-between comments, I copy & paste the desired version on a new chat, and rename as "archive - code XYZ" for the previous one.