Go into Club/Stadium Facilities/Stadium Expansion.
Change the stadium type (rounded corners, oval; this will cost
you money) and select "Build Stadium". Do this again
(changing the stadium type, build it), and you will receive money.
Note: Do not do this if you are thinking about building a new
stadium.
Trainer: +1 v1.00 by Hoodlum
Trainer: +1 v1.01 by Hoodlum
Trainer: +4 v1.00-1.01 by PWZ