Once you enter a plea and accept the offer by the DA, you cannot go back and change the plea except for in very limited circumstances. This is especially true after you have completed all of the conditions of the agreement and if ten years has elapsed as you have indicated. So, short answer is no, you cannot now go back and have the original charge reduced to a misdemeanor. However, depending on the type of plea that you entered and the circumstance surrounding that, you may be eligible to have the conviction expunged. My recommendation would be that you consult with an attorney to see if you might be eligible for this.
This communication does not create an attorney/client relationship. My answers are intended for educational purposes only. No action will be taken on your behalf without a written retainer agreement. I am licensed only in Tennessee. Therefore, if you are outside the state of Tennessee, it is recommended that you consult an attorney in your jurisdiction.