Originally Posted by Often1

It's called Hidden City and it's a violation of DL's COC. There are at least a thousand threads on FT about it. If you do it, don't use your FF#, don't check luggage and don't do it often. You risk having your SM account zeroed out (I mean closed with 0 miles), having your ticket refared to the LAX-JFK and, In IRROPS being rerouted to your ticketed destination, PHL, not to your connection point, JFK.

If it's work-related don't do it because many businesses frown on employees who defraud other businesses.