Reports can be found in the standard Android file system, in a folder titled 'SiteAuditProReports'. Reports can be manually transferred to a backup location and then removed from device by deleting the contents of this folder.
Accessing your reports on your Android device
1) Connect device to computer
2) Open your Android file browser
3) Navigate to the folder named 'SiteAuditProReports'. This folder will contain all of your generated PDFs.
4) Copy these over to your computer.
Deleting a PDF from this folder removes it from your device.