That depends on your chain of command’s willingness to respect your change of position. There are several possibilities.
Option 1: You could type a statement up and take it to the individual who counseled you and state something like: “I wish to change my position from agree to disagree.” If they allow you to make the change, simply cross through Agree initial it with a time and date. Initial disagree and then in the comment block write: “Please see attached statement dated: _____.”
Option 2: If they do not wish to allow you to change your decision, request that a copy of your statement be placed with your counseling statement. If they refuse, see the 1SG and ask for a copy to be filed with the counseling statement. If he disagrees, keep a copy of the statement in your records with a note stating that you attempted to provide the statement and were not allowed to attach the statement or change your decision. You should include who you spoke with, the time and date of the conversation, and the name of anyone who was in the room at the time.