Early writing includes both transcription skills (e.g., handwriting and spelling) and composing skills (e.g., the generation, manipulation, and translation of ideas into writing), yet early composing is not as well understood in academic research or by classroom educators. This study seeks to understand 1) how children retained or modified core idea units from pre-writing verbalizations to post-writing verbalizations and 2) how these transformations are related to other composing components, such as connection of ideas. Participants in this study included 133 children at the end of their prekindergarten year. Children completed two composing tasks related to planning a birthday party: an Invitation task and a List task, in which they were asked what they planned to write before writing and then what they had written after writing. Results indicate that most children's pre- and post-verbalizations were connected in meaning. While children overwhelmingly modified their core ideas on both tasks, more children retained ideas on the List task than the Invitation task. Children most often concurrently added and deleted ideas on both tasks, but did so less often when pre- and post-verbalizations were connected in meaning. Implications for supporting the complete writing process, from planning to review and revision, in classroom practices as well as further directions for research are discussed.