Dynamics GP presumes that any document that you print becomes a critical document in the business cycle and typically, does not let you delete it. But sometimes, you must delete it.
What to do?
The SOP module keeps track of the number of times you have printed a document. If you print it once, and printing to screen counts as printing, you cannot delete it. Therefore, you need to set the system back to believe it has never been printed in order to delete it.
Of course, this is not a supported solution, so use it at your own risk. The first step is to back up your System (DYNAMICS) and company databases. The name of your company database is displayed on the Company Setup window.
SET TIMESPRT = 0
WHERE SOPNUMBE = 'your_SOP_Doc_Number'