Please by notified that it has been a year since signing the contract with your corporation, and according to the contract I am entitled to 21 days of annual leave. I would like to request a leave, and hope you accept.
Remarks about the translation
the formal arabic is always different from the formal english, the first statement is simply a salutation, that i think rather be summarized in fewer english words, the last statement "hope you accept" cannot be used in english formal form, but it does fit in the arabic form, i guess this should have been a "meaning only" translation