Originally Posted by Often1

The hidden city ticketing issue vastly complicates OP's situation. Generally, asking to "link" separate tickets does nothing. Here it actually may hurt as it would cause an agent to look at two tickets and see that they are "impossible."

The same thing goes for asking a check-in agent for help or for help if a no show. Agents will look at the ticket and see that OP is asking to be sent to a new destination.

While this may all work out and sometimes does, OP should go into this presuming that if he no shows for the ticket he does want to fly, that he will have to purchase a new ticket.