my soon to be ex-wife agreed to change her name back to her maiden name as part of our separation agreement and has not done so. what can I do? she is

The name change can be done very simply as part of the divorce and will be granted at the same time that the divorce is granted.  There would be no reason for her to file a separate name change petition prior to that.  However, if she changes her mind and decides to keep your name, I do not think this provision of your separation agreement would be legally enforceable, as people are generally allowed to change their name to whatever they want.  She could change her name to match yours even if she had never been married to you.    This answer is given in accordance with the laws of Virginia and may not be applicable in any other state.  It should not be construed as legal advice, as that would require a more thorough analysis of all of the facts involved in a specific case.  If you need further information or assistance, please feel free to contact my office for a consultation. Case results depend upon a variety of factors unique to each case. Case results do not guarantee or predict a similar result in any future case.