i have to write the letter to the Simen's CEO about an asking for their helping to open an operate room and all of the machines in Thailand subway(doesn't open for the public use)they are the company who's take care and repair about the electronic train in the subway) on children's day.

i don't know how to start to write the letter. could you please help me for reply an advice. i must to send to my boss tomorrow... thank you for your kindly advice
I am not sure that I really undersand your posting.

You need to start with an brief introduction to yourself and your company, then move onto what you want from them. You need to start the letter and then post your effort back here for comment.
also, make sure you spell their name right - is it Siemens?