I am sorry. I am not feeling well and I won't be able to attend work today.
I am sorry. I am suffering from stomach infection and I need to take sick leave today.
I'm not feeling well. I want to ask for sick leave this afternoon.
I've got a cold. I'm sorry that I need to take sick leave today.
I would like to get today off as I am feeling sick.
I have to inform you that I cannot go to work today because of illness.
I would like to request a one-day leave of absence for personal reasons.
I would like to request a leave of absence from [April 1 to June 30].
I would like to request a formal leave of absence from my job. I plan to be away from [July 1, 2018 - December 31, 2018, returning to work on January 1, 2019.]
I will check my emails during my holiday.
I can be contacted while I'm away.
I apologize for the inconvenience my absence caused.
I will make sure that I hand over all my responsibilities to Mary and explain everything to her.