How to ask leave to manager..?

it is tough situation. i know how tough the situation can be when its delivery time.still try to put your points to your manger in a decent way.

You can try and finish what you need to accomplish? It might put things in your favor and finally get your boss' signature. Or better yet, talk to your boss. Tell him why. I do understand that there are lots of types of managers out there. Do what you need to do first then if your boss doesn't approve it, don't be afraid to ask why. If he/she disapproves it and he/she can't give you any valid reason why you can't take your leave, take action then. go up the ladder a notch. If he/she approves your leave, well and good. Oh, and give enough time for your leave. Request at least a week or even two weeks ahead.