The instructions are in the post you replied to but sure, let’s spell it out…
- Take all of your current hero’s gear off and put it into your Stash
- Do the same for your hero’s followers
- Make a note of their build, i.e. which abilities / runes they have
- Delete that hero
- Create a new level 1 hero with the name you want
- Shout out in General Chat in-game and ask for a power-level
- The power levelling process (where a level 70 runs you through a couple of Torment 6 Nephalem Rifts) will get your new hero to 70 in 10-15 minutes
- Put the abilities / runes you made a note of at step 3 onto your new hero
- Take the gear out of the Stash that you put in at steps 1 and 2 and put it onto your hero / followers
- Re-allocate your paragon points