Dear Sir,
I am writing 
this
 letter to inform you that I will not be able to continue my evening course in which I am currently enrolled. 
As I am working in Walmart as a Service manager It is hard for me to focus on part-time studies. Sometimes, long working hours at my job make me tired Linking Words
Due to
 Linking Words
this
 I am not able to concentrate on my study. In a couple of weeks, my Manager is posting me at a high post  so there will be more work coming for me.
Since my Training is going to start in three weeks for my new Role I will not be available in the evening. Linking Words
However
, I will have to join the training session for Linking Words
this
 posting as well which is After 6PM.
I will appreciate that if you could postpone my class till August So that I could available till that time.
Hopefully, You will understand my concern and try to cooperate with me. I look forward to hearing from you.
yours Sincerely,
Prabhjot SinghLinking Words