Can I skip the outbound flight and only take the return?

No, you cannot only use the return ticket. To guarantee that the airline keeps your return ticket, you must travel on the first part of your trip to your final destination. For example, if you booked London - New York - London, you cannot use the return as a single ticket from New York. You must fly London - New York first to travel back on the ticket from New York to London. 

The airline will cancel your return flight and you will not be eligible for a refund if the outbound flight is not used. Please note that sometimes (not all the times) there is an exception from this rule when two separate tickets are issued for departure and return. In such cases, some airlines allow the passengers to use only the return. However, this should be checked separately from case to case. Please contact us to verify.