I presume you mean the General Aviation Rerport from
That can be edited within Adobe Reader version 10.1.3
It probably can in earlier versions of 10
Open the file in the program, then click on the button top right marked "sign"
When the menu appears select "add text"
It takes a few minutes, but eventually an interactive cursor appears which you can use to mark locations to insert text
You can add a signature if you like, and then click on "done signing" to merge the changes
I suggest you work on a COPY of the original document - not the original download, just to try to avoid multiple downloads