It is not possible to exercise a short option position.
The TWS option exercise tool will display non-actionable short option positions in the bottom half of the window. More information on TWS Option Exercise tool can be found in our Users' Guide.
Please Note: When you sell an option, you provide the purchaser with the right to exercise which they generally will do if the option is in-the-money at expiration. While it is unlikely that holders of in-the-money long options will elect to let the option lapse without exercising them, certain holders may do so due to transaction costs or risk considerations. You can not force an assignment of your short option on the owner of the long option. Always review your position overnight as expiration stock option closing transactions will be viewable in your Trade Confirmation or Activity Statement the next day.