Fight the ticket. The state will have to have her testify, & if she doesn't show up, the state is SOL. Since the officer didn't see the incident, most of what the officer can testify to is hearsay & inadmissible. (Anything *you* said is admissible, so I hope you didn't admit guilt.)
An illegal lane change generally means changing lanes in an intersection or in an unsafe manner. Unsafe would cover changing lanes without doing a head check. Since you made 2 head checks, you can argue that she must have been doing something to contribute to the accident -- speeding, moved into the left lane, etc. You can also argue that you did not actually change lanes. Did you hear/feel your tires go over the reflective road turtles?
If you post the exact code section you are charged with violating, we can look it up. Or you can look it up here: [url]http://leg1.state.va.us/cgi-bin/legp504.exe?000+cod+TOC[/url]
This post does not constitute legal advice, nor does it create an attorney-client relationship. Postings are based only on the information provided and you should consult an attorney in your area before relying on information contained in this post.