There is no built-in way to do it.
PDF is a display format, not a processing format. All flow information is lost. What you see is a collection of unrelated text boxes containing homogeneous text (same fontface, weight, size, …). At best, you can recover these bits as separate pargraphs and you’ll have to rebuild the original paragraphs by merging bits. Also, styling information is lost: page, paragraph, character.
Making a Writer document from PDF is possible but this is mainly a manual task. Raw text can be pasted as unformatted. From there on, you recreate the real paragraphs and reformat the text. Refrain from direct formatting. It is not faster than a more systemic approach with styles. Working with styles is easier when it comes to fix formatting errors.