Are you saying you had to incur attorney expenses to get the IEP? Is this because they initially denied it? If you, I absolutely wouldn't give up anything you have.
An IEP is something to hold onto, although it is true that the document is only as good as those who are implementing it. In a good, caring, supportive school, a 504 could be just as good.
If your daughter is not getting special services with her IEP, you can change that. Rather than get rid of the IEP or "reduce" it to a 504, improve the IEP! Get really specific stuff in there to support your daughter in school. If she has "outgrown" it, new goals should be added. Transition to high school might be a big upcoming issue, new social demands, organization of homework and study materials (executive function issues), etc.
One thing you can do (if the meeting is/was postponed) is go back to every teacher who has worked with her, all the way back to kindergarten. Create a form for them to fill out, where they can easily check yes, no, or maybe boxes (or do a scale of 1-to-5 for responses). Ask them how much support they feel your daughter needed, ask them about specific issues your daughter deals with, and if they feel IEP support has helped her access the curriculum, etc. Bring copies of all those filled-out forms to the IEP meeting as your evidence that not only do you need to keep the IEP, but you need to improve it since your daughter has "outgrown" the current one.
