To remove one redaction: Right click on the redacted text and choose Delete. This will remove the shadow Redaction box from that section of the document:
To remove all redactions in the document click on the click the Clear All Redactions ( 
) button highlighted below:
To avoid inadvertent removal of redactions you will see the following Warning pop-up box. You must type the word YES (in all caps) and click the OK button to continue to clear all redactions:
NOTE: In order to un-flag a document containing existing redactions, remove the redactions from the image.