There is a timeline specified by law. Here is the link for FCPS paren Resource Center which should have info about your rights.
http://www.fcps.edu/cco/prc/faq.shtml

Anyone know if we have any rights concerning IEP meeting being cancelled for second time due to evaluations not being completed by specialists? We are new to the school, so need an IEP update for THIS school year. What should we do? TIA.