If you use our sequences, you might have seen the option to reply to last thread or start a new thread. These are options that give you the ability to group your emails together or break them out. They are sometimes referenced as "conversations" too in some email programs.
What is a thread?
To simply explain it, a thread groups several email messages together that are part of the same conversation. This is what it looks like in Gmail.
Why can't I change the subject and reply to in the same thread?
In the land of emails, you cannot change the subject line if you want them grouped up together. This is something that is out of our control.
What happens if I change the subject line after the first email has been sent?
If you change the subject line after the first email with the original subject line was sent, it will update for new contacts added to the sequence moving forward. The second email in the sequence will keep the newly updated subject line for those new contacts as well.
What happens to previously sent emails containing the old subject line after it's been updated?
If the first email in the sequence sent to a contact has the old subject line, the second email will send with that same subject line. The second email will not update with the new subject line since it needs to have the same subject line as the first email to be in the same thread.