Constructing object

I have a query in constructing an object and storing it in database in json format.

Its in air domain industry. Need to construct an ojbect and store it in database in json format so the other applications can use the same object for various test automation scripts.

What i have done is i have created a class called PassengerDetails and inserted to station, from station etc., as below.

class PassengerDetails{

private String toStation;// Origin
private String fromStation;// destination
private String noOfAdults;

and getters and setters. 
}

The passenger type also changes, like infants, companions etc., and i am not understanding how to handle it in class PassengerDetails. I have a guess like i have to add another class for PassengerType. Please correct me if i am wrong and suggest me how to add that passengertype details.

And I have created one ticket class (one ticket for each passenger, if 3 adults are there then 3 tickets and and three tickets are associated with one unique PNR). Here we have to store how the ticket is purchased, i mean by cash or credit card

class PaymentDetails{
private String creditCardType;
private String creditCardNo;
private String creditCardHolderName;
private String cash;


getters and setters.

}

We are having different payment types like Creditcard, cash, vouchers, refund amount etc., I am in confusion again how to handle this in the above PaymentDetails Class and how to link this class with TicketInformation and PassengerDetails

class TicketInformation{
private List<PassengerDetails> passengerDetails;

Getters and setters...

}

For multiple tickets, we have one PNR.

class PNRDetails{
List<TicketInformation> ticketInformationList = new ArrayList();
getters and setters. 

}

Now i have a query like, if there is modification in flights or dates etc., new ticket will be issued. Now the question is how to store this new tickets and old tickets so that the user who retrieves the list of tickets can understand that there is a modification and hence there are new tickets and old tickets.

The other scenario is that if there is an addition of additonal passenger then not only the ticket changes but also the PNR changes, Now the question is i want to store both new and old PNRs and associated tickets.

For multiple PNR's how to write the class, do i have to write a class where it has List as instance variable. I messed up the code and i am in confusion. Could any one suggest better approach in modifications of code.