Bamboo army glass

How to write a proper letter to the landlord to break a lease agreement? any sample? thanks!? - sample letter lease expires

I left the house in renting now because of the problems in the family. I share the car with 2 other guys. I am the only way out, but since three of us signed the lease together, the broker told me that I must write a letter to the landord why I go. What kind of letter you write? an official letter? informal? Can I sample of writing? IM in the shit. T_T