H1B to EAD transition

Hello, buddies. I have a question regarding to change from H1B to EAD. Currently, I work with H1B. But I need change an employer next month. Since I have used AP last year and also the future employer is governmental. So I even never think about H1B transfer. Due to rush change, there may be several day gap between my H1B and EAD. I don't know whether it will affect my I-485, which is still pending. Your help is highly appreciated.