We have developed a model of requirements for a travel agency system. There are two types of user members: premium and free. Both users can cancel their previous reservations. Unlike Premium users, free users must pay a cancellation fee as a result of a cancellation.
In the use case diagram of the previous functions, we have the following problem: should we distinguish the
Cancel use for different types of users? In other words, when a free user makes a cancellation, he must include the use case of the payment of fees. But we also know that canceling reservations is an identical function for both types of users (although this may lead to another use case if it is a free user). We are therefore not sure that a single use case is sufficient to demonstrate the system's capability. In addition, we should use extended relationships to show that this can sometimes include paying the tax. But if two different use cancellation cases are used, we can explicitly show the relationship of inclusion of a free user. We will appreciate any suggestions. Thank you in advance.