Put livestock in a bucket or tote with aquarium water. If it'll be more than 30-45 minutes, drop in an airstone on a small pump to move the surface water a bit. Then finish draining the water out, scoop out the substrate in to another bucket, take all the accessories of. Move tank. Reassemble all in reverse order. Don't forget to dechlorinate your new water. It'll be nice and clean and good to go since your filter is already cycled I'm assuming