Jozlyn

In my 2017 Traverse the driver's side seat will not stay in the raised position. This is a manual adjuster and I pump it up and within a day it has moved down. I took it to the dealership and all they could do was have me leave it so they could keep checking it throughout the day. Due to a death in the family, I haven't been able to take it in and leave it. They tried checking it over the short time they did have it for the oil change but couldn't duplicate.
Is there something that I'm missing, a step that would lock the seat in the position that I want? What type of mechanism is it that moves the seat up and down? Can that be replaced?
Thanks for anything that will help.