Desolder the sides of the cartridge reader using the soldering iron and desolder pump.

Refer to this soldering technique guide for reference

Patiently wait for the cartridge reader to cool down after being desoldered.

It's very important to remove all the tin from the motherboard and cartridge reader before lifting it from the motherboard. Failure to do so could damage the motherboard.

Carefully lift up the cartridge reader. A plastic spudger might be helpful in order to easily remove the cartridge reader.