Can I update Transaction Document after saving it

I created a Transaction Document for Purchase Transaction Type. Clicked save and ended work period. The next day I noticed that instead of 10000 grams of coffee received I only typed 100. Since this is tied to the document/invoice received, can I edit and update that document? Or do I have to create a second document? I can open the document and edit the fields but the SAVE button stays grayed out.

No you can’t change past transactions.