How to remove glass in between Bosch electric oven door

Whilst cleaning the glass part of a Bosch oven door, some liquid oven cleaning solution seeped through the middle part of the glass leaving a very large smear. Due to the fact that the glass is placed inside the door, there is no way of getting to it and believe me we’ve tried. Other then replacing the glass is there any other way around it? If replacing the glass in the middle is the only way- how do we do that? Who is the best person for the job? How much would it approx cost? Some advice would be appreciated.