Dear Sirs, In American business English, we would not say this. If "Dear Sirs" is a common way to start a business letter where you are, then it's fine. But if you are writing to your own boss, wouldn't you use his/her name?
This is to inform you that My Air ticket's validity will expire on 10th May 2008. So i hereby request you to grant me the Home leave as per Bank's rules and regulations. Your company has regulations about letting you use vacation because of expiring airline miles? Make sure you capitalize I. Is "home leave" a specific type of leave? Is there a reason to capitalize it? There's no reason to capitalize "Bank" and it needs an article/determiner.
I have tickets with an airline that will expire on 10th May 2008, and would therefore like to take X days of leaver, from [date 1] to [date 2], in accordance with company rules.
Gulf Exc will not allow to appoint anyone else from outsource in our replacement. As per Mr Ramesh Badjate our bank has to arrange for our replacement.
I have absolutely no idea what this means.
So pls advise , and hope you'll grant my leave application. Please let me know if you approve this leave request. I appreciate your consideration.