Time off work

Dear Mr. Hood,
I am writing to you to request your authorization to take some time off work during the next summer. Allow me to elaborate on exactly why I need this.

As you know, my son is an excellent football player. He has been playing for the under 17 national team for the last 2 years. The last week he received an invitation to be part of the Italian team Juventus for one week. This is really important for my son because if he does it well he will be transferred for 2 years.

The invitation is for one week from February 1st, but they recommend arriving one week earlier. So, I need to take time off work for approximately 2 weeks, from January 24th to February 8th. 

I talked with James Smith and he is willing to assume my responsibilities during this period. I would like to mention that during the summer, there are less incoming calls, so it is absolutely viable.

I look forward to hearing from you.

Yours Sincerely,
Francisco Zuñiga

for refers to a period of time, we use during for events, like a presentation, a class, etc.

We use -ing afer recommend.