How to write an abstract for a summary paper based on a longer paper? I wrote a 50-page report that has an abstract. Now I have to write a shorter paper on the same topic that summarizes the report.

The challenge is that the most logical thing to do would be to simply use the same abstract for both papers.

However, it seems to be an unwritten rule that abstracts should not be reused. (I am wrong?)

Alternatively, I could write a new abstract from scratch, ignoring the old abstract.

What would be the best course of action in this case?
First, write a new one without looking at the old one.  Then, compare the two and see if you missed anything.