Can I exercise a long call option in a demo Paper Trading account?

You can elect to manually exercise or lapse long options positions only. 

To exercise an out-of-the money option you must first select Allow Exercise, which indicates that you understand that exercising an out-of-the money option will result in a monetary loss. You will only see this preference if you select an OTM options position…

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If a long option is not in-the-money by at least $0.01 at expiration it will not be automatically exercised by OCC. If it is in-the-money by at least that amount and you do not wish to have it exercised, you would need to provide IBKR with contrary instructions to let the option lapse. These instructions would need to be entered through the TWS Option Exercise window prior to the deadline as …

There is currently no feature available that will automatically enter an early option exercise for you when an American Style option's underlying trades at a specific price. However, accounts that hold dividend-paying positions that may be affected by early exercise will receive a notification via email or IB FYI notification, and in the…