Dear______,
Muchtomyregret/IamterriblysorrythatIamunableto______.ItismainlybecauseatthattimeIwillbefulloccupiedbywhichisquiteoutofmyexpectation,andthatconflictswithyour.ThereforeIamforcedtoadjustmyscheduleandcannotmakemypresenceonyour.Isincerelyhopethatyouwillenjoyagoodtime.Bytheway,canwehavedinnertogethersometimenextweek?Ihopetoseeyousoon.
IamreallysorryagainandItrustthatyouwillunderstand.
Yourssincerely,
LiMing