How to delete an individual text from a conversation

I have been having ongoing issues with deleting individual texts from a conversation ever since I installed IOS8. First, I couldn't get the trash can icon when I pressed MORE. I read that restarting it would make the trash can icon appear, although it would only work a few times before I would have to turn the phone off and restart it to get the trash can icon to appear. Now, although the trash can icon appears, my only option is to DELETE ALL. I would like to fix this once and for all!