First, unwind the cord from the machine and try to pull the wand again.
It is poorly designed, in that if you have the cord wound on the machine, it ties the 2 parts of the vacuum together.
If this doesn’t work, look at the space between the chrome pipe and the white plastic where the 2 pieces come together.
If the space isn’t even on both sides, the unlocking mechanism won’t work. Apparently there is just enough space where it will stick in and not come out. if it isn’t properly aligned.
You can try hitting it with your fist to push the larger spaced side in more, or if that isn’t enough power, take a small hammer and a block of wood and tap on it gently until it moves into the correct space.