Dear Sir/Madam,
I am sorry to tell you that I may be not able to paticipate in the training that will be held soon. According to my work issues arrangement, a buniness trip must be taken urgently during theses days, so i have to miss the training. Of course, as you know I am eager to join the training because it would provide me with a good opportunity to share information and communication. However, if there is still a chance after the training I will be very grateful to discuss with you about it.
Thanks again for your understanding!
Yours, ###
