Automatic re-labelling emails

Question

Is it possible to have Gmail automatically label emails based on existing labels? For example, I have "Follow Up" and "Waiting Response" labels. What I would like is for Gmail to automatically relabel a conversation from "Waiting Response" to "Follow Up" when I receive a reply. I do not want to "Follow Up" all incoming mail, and I don't always want to "Follow Up" particular people or addresses.

I am well aware that I could simply flag important conversations and look to see whether I was the latest respondent, but I want an automated system for a series of reasons I won't bore you with.

So, is it possible?

Answer 1

Unfortunately, no, this isn't possible with just Gmail filters.

You can search for label:Follow up, but that switch won't work for a filter. (Mostly because labels are actually applied to individual messages and not conversations.)

At best (short of a Google Apps script) you can save a search for label:Waiting for is:unread, which should find you any messages in a conversation with your label that are currently unread.