To reset the spellcheck in a Microsoft Word document, click the Microsoft Office Button in the top left corner. Next, click "Word Options" at the bottom of the menu. In the dialog box that appears, select "Proofing." Under "Correct spelling and grammar in Word," click "Recheck Document" to reset spellcheck.
Once spellcheck has been checked, click "OK" in the Word Options dialog box to go back to the document.
This will reset the spelling and grammar checker so that the words and grammar that have already been checked, changed or ignored will again be recognized by Word so that new changes can be made.