Stuck

The days hastiliy paving my departure for the states. But I'm feeling stuck.

1) The airline made a mess out of our departure dates from SG.
2) Without the exact departure date, I can't request the US employer for a change in end date as yet and I've gotta submit that request 3 weeks prior to arrival there.
3) I don't know if my request to the US employer will be successful.
4) Have assumed that my request will be successful and have decided to depart from LA. So should the request not be successful, I'll be travelling to LA to take my flight back to SG which is dumb considering the fact that NY is nearer and I've not been to NY but I've been to LA.