No holiday

Meanwhile over the other side of the office, Lester was getting to grips with the company portal holiday booking system.
John: “You’ve booked the 20th & 21st. That's two days.”
Lester: “No, I’m only booking off the 20th. I’m coming back on the 21st.”
John: “You need to book the start date as 20th & end date as 20th.”
Lester: “That makes no days doesn’t it?”
John: “No you twonk, it’s one day’s holiday.”
Lester: “What do I have to do if I want no days off then?”
John: “Don’t put them on the portal then!!”