Hazel: hey 
Jason: Hi Hazel
Jason: I texted Marc
Jason: he is going to replace you today 
Hazel: Aw thanks a lot for your help
Hazel: I have to go see my mother today
Jason: That's fine 
Jason: Let us know if you're going to be on Tuesday so that I can find a replacement for you
Hazel: Thank you
Hazel: I will probably let you know by tomorrow 3pm
Jason: No worries
Jason: Take care
Hazel: Thank you! 
Jason has texted Marc, who is going to replace Hazel today, as she has to go see her mother. By tomorrow 3 p.m. she will let Jason know if she's going to come on Tuesday. 