How to update your post heading for 2018
Change the post date to make it look new
The next thing to do is to change the post date.
This will make the post move to the front of your blog and make it appear brand new.
(You can do this one at the same time that you do step 1, but I chose to make a separate step of it here).
Open the post for edit, (or most likely you are already in the same post).
Go to the PUBLISH section at the top right side and click EDIT beside the date.
Then edit the date to the current 2018 date.
Be aware that you will need to wait until 2018 to do this. If you do it now, your post will be left unpublished and disappear from your blog until the future date you have chosen.
Click the blue UPDATE button and you are done.
Next: Telling Google what we did