Life insurance contracts are characterized by very long durations. Since personal needs of policyholders may change over time, policyholders are entitled to change or cancel the insurance contract during the policy term. The exercise of these contractual options by policyholders constitutes a financial risk to insurance companies. Therefore the financial impact on cancellations or changes of life insurance contracts must be considered when evaluating the risk of the insurance portfolio. In accordance with Solvency II, the modular approach of the standard formula is used to calculate capital requirements of insurance companies. The calculation of capital requirements in the lapse risk module is based on three separate shock scenarios. This scenario-based approach is described in the present thesis. Furthermore a simulation model is presented, which covers endowment policies of a life insurance portfolio. Therefore premiums, reserves and benefits are calculated, taking into consideration cancelled insurance contracts. In the model, three separate shock scenarios on lapse rates are performed and the one with the maximum impact is determined. The penultimate chapter contains a mathematical examination of the calculation of reserves regarding expected policyholder behavior. The focus is on Markov chain modeling of insurance risk and behavioral risk in terms of free policy risk and surrender risk.