These blinds have metal side channels. For instruction on how to remove this blind, please click on the below link.
Removing a VELUX Blind
These blinds have wooden side channels.
The top section of the blind can be removed by gently rocking the cassette back and forward until the pins disconnect from the sash. Depending on the age of your blind the timber fascia and blind will come away in one section or will be two seperate sections. If this is the case the roller section is removed by disengaging it from the side brackets, the brackets will also need to be removed. The wooden notched side channels are pinned to the window sash, these can be removed by gently prising the timber side channel away from the sash using a flat bladed tool. Place a piece of stiff cardbpard under the blade to avoid damaging the edges of the sash.