Let’s say a paper is a house – new construction. The owner is the professor. He or she determines the basic scope of the project, the size and shape. The professor tells you what to write: a two page reflection paper, or a 600-word précis or an exegetical paper with three specific sections.
Some professors (owners) are more involved in the details of the paper than others. Some choose every fixture and paint color while others leave most choices to the architect/builder.
The architect/builder is you, the student/writer. You take the owner’s instructions, and create the design. You choose a topic (floor plan) and organize the ideas (plumbing and wiring systems). You do the research (hire sub-contractors) and shape it into its final form, attending to all of the details. You revise and copy edit (go back and clean up the site), so every mistake is made right.
The architect is not the owner. She can't design a ranch house when the owner asked for a cape cod. She will get fired if she does that. Similarly, a summary is not equivalent to a reflection paper. You have to do what the professor asks.
The architect is also not merely a collector of subcontractors (sources). He has control. He shapes and crafts the plan (argument). He is in charge of how the details are arranged and executed. He is making a new thing.
The paper/house must conform to the specs (specifications) of the professor/owner, but the writer has freedom to design and shape within those boundaries. Not unlike the relationship between God and human beings in the garden. (No, I do not think professors are equivalent to God.)
Accept the boundaries, and go for it: design a functional, beautiful space/a creative paper, just what the professor ordered.