1. Create a list like this:

• row 1
  • row 1.1
  • row 1.2
• row 2
  • row 2.1
  • row 2.2

2. Select all of 'row 2' and delete it

3. you'll end up with either something like this where row 2.1 has double-bullets

• row 1
  • row 1.1
  • row 1.2
  • row 2.1
  • row 2.2

or something like this:

• row 1
  • row 1.1
  • row 1.2
  • row 2.1
    row 2.2

or something like this where you can't delete the empty row:

• row 1
  • row 1.1
  • row 1.2
• • row 2.1
  • row 2.2