"But I'm not saying goodbye … I think you'll have to see more of it on the new season, season 18. It isn't airing yet, but it's being filmed. Currently, in this room."
Khloe hoped Kourtney would return to the family's reality show at some point.
"We definitely love Kourtney and we will miss Kourtney and whatever she decides to do, but people come, people go all the time in this family.
"We feel like it's a revolving door, so Kourtney might leave this week, she'll be back. They all come back," she said.
Kourtney is mum to three children with ex-partner Scott Disick – sons Mason, nine, Reign, four, and daughter Penelope, seven.
Kim and Khloe joked Kourtney quitting the show could lead to a spin-off show.
Kim, 39, joked about what the title could be, suggesting: "Just Kim And Khloe Take …"
Khloe then added: "Take Calabasas! It's just Kim and I now."