A potentiometer has constant resistance. The wiper point moves.
If you want a variable resistance, you can use a potentiometer by connecting to the wiper and one end.
To limit to 2kΩ to 6kΩ, you can physically limit the travel, or you can put a 6.666kΩ (6.8kΩ would probably do) in parallel with the potentiometer and a 2kΩ resistor in series with the combination.