You can remove skills marked Added by you. Skills your job role or target role needs, and skills someone assigned to you, have no Remove Skill option.
Remove a Skill
In the sidebar, select Grow.
Select ⋯ on the skill's row, then Remove Skill.
Select Yes, Remove.
Remember❗: This can't be undone: your self review and other people's reviews of the skill are deleted. If you add it again, it starts at the level you choose, with no other reviews.
You'll see skill removed, and the skill disappears from Grow. Skills Activity records "You removed skill from your skill set."
Good to know
If the skill was a focus skill, removing it frees up a focus slot.
Any review requests for the skill that are still waiting are cancelled, and you get a notification for each. The request disappears from the reviewer's Inbox.
Nobody else is notified when you remove a skill, including reviewers whose requests were cancelled.