NeoLoad does not have a Ramp Down feature like you have for the Ramp Up.
However, there's two different ways to have a kind of ramp down at the end of your test. You can pick one or the other depending on your script configuration.
The first way is to configure your population to not stop the virtual users when the configured duration is reached. Instead you can configure it to let the user finish their scenario.
This is configured in the "Advanced" section of your populations.
You should get an irregular ramp down but it should work.
The second way is to use the custom policy instead of the ramp up policy. It's not straightforward as ramp up policy but you will be able to control the ramp down a bit.
