Secondary market

Ticket Exchanges alternatively known as Ticket Brokers, allow the public to advertise, trade, sell, and buy unwanted tickets online.
For example, say you bought tickets to the football and you can’t go or you’re a season ticket holder but you don’t attend every game. Ticket Exchanges allow you to trade your tickets with other fans wanting to attend these events. This gives the consumer the chance to recoup there hard earned money. In some cases ticket exchange's have been used by ticket scalpers to sell tickets. Scalpers would purchase tickets in bulk from the promoter hoping that the tickets would sell out causing an increase in demand for tickets and thus an increase in the ticket price, which allowed scalpers to profit on this margin.

Ticket exchange in air travel

There are online marketplaces where private persons can offer their transferable flight tickets for sale. For travellers without a travel insurance, it can be a good way to cover the costs for a flight cancellation due to medical, personal, or professional reasons.

Flights are transferable, if the name on the ticket can be changed. US-based airlines are very strict about changing names on flight tickets, even a small typing error might force a traveller to buy a completely new airline ticket. In UK and Ireland, the sale of flight tickets is strictly regulated by the Civil Aviation Authority (United Kingdom), and only agents authorized to Air Travel Organisers' Licensing

Air Travel Organisers' Licensing

Air Travel Organisers' Licensing is a United Kingdom Civil Aviation Authority scheme to protect people who have purchased package holidays and flights from a member tour operator....

are allowed to sell flight tickets. Even though several British airlines allow name changes, the customers are not allowed to resell their flights. In other European countries, such as Germany, France, and Netherlands, the exchange of flight tickets by private persons is not prohibited.