Originally Posted by
Often1
The general rule -- subject to OP providing the proper data -- is that one must fly all segments of a ticket in the order issued. Not always the case so it's a non-specific answer to a non-specific question.
All the specifics are in the OP.
And would you be willing to guarantee, for any other specific case, that the person asking the question could skip the second and third sectors on their ticket, and happily take only the first and fourth sectors on their ticket?