In "Lines Composed a Few Miles Above Tintern Abbey" by William Wordsworth, the speaker (Wordsworth himself) most significantly uses apostrophe when addressing his sister, Dorothy. He turns from describing nature and his reflections to directly speak to her, expressing his hopes that she will benefit from nature as he has.
Example lines:
"My dear, dear Sister! And this prayer I make,
Knowing that Nature never did betray
The heart that loved her..."
This emotional address to his sister is a clear instance of apostrophe, as he shifts focus and speaks to her directly, even though the poem is meant for a broader audience.