Roles Exchanged

Doctor informs Chandramukhi about his experiment and also reveals to her that he will conduct an experiment in Imaan Chowki after which their characters will change. Chandramukhi becomes Gopi, Billu becomes Chandramukhi, Gulgule becomes Billu and Gopi becomes Gulgule. Next day Scientist's laptop breaks because of Bhola Pandit. How will they get back to normal now?