Seeking some help from experienced.

I am planning to change from F1 to J1 status within US. If any of you has gone through that process, I was wondering if you could share your experience with us.

First of all, is it possible to do within US? If yes, how long it will take? Is there any expedite service available for this? If so, how long this expedite service will take?

Thanks for your time and suggestions.

Dharan