Need your help to correct this letter

[muzokh]

Hi
I'm wondering that if someone correct mistakes from the following letter, Thanks I advance.

Hi Sobi


As you know that I did some addition hours on weekend for Windows upgradation and in order to adjust those hours I’m planning to take few hours off , please see below schedule for details


--12-Sep-2017 Not available after 1 pm
--13-Dec-2017 Not available after 1 pm
--14-Dec-2017 Not available after 2 pm


Thanks

Muzokh

 

[tedmc]

What is the purpose of the letter? Who is the writer and who is the receiver?
Is it a request to take time off to compensate for working overtime? What do you mean by "not available after 1/2pm?