Gotten a few asks so I might as well give you a tutorial :)
1. Find the comment(ignore what mine says)
2. Mark it and copy it.
3. Make a text post and paste it, it will be white, don’t worry.
4. Click on “html” twice.
5. Click on the line after the last letter.
6. Click enter and “block quote”
7. Write your reply and post it! Remember to tag the blogger so he/she/it can see your reply :)