Consider the following scenario for a passenger booking a train ticket:

The applicant would check the available trains on a specific date using the user interface.

The system would search for the available trains on that date and present them.

The applicant would select one of the trains routes and time of departure.

The applicant would provide payment using a credit card.

The system would update the number of passengers of that train.

The system would associate the passenger details with the ticket number.

a- Draw a sequence diagram for the above scenario with a minimum of 4 objects and 6 message calls

b- Draw another (conditional) sequence diagram for implementing the below exception:

If the passenger has a loyalty membership, he should benefit from a discount.

This is from TM345