To disconnect a gas oven, begin by turning the ball valve on the flexs connection off, and then, using an adjustable wrench, loosen the valve on the stove and open up the stove's window. You may need to take other safety precautions, depending on the make and model of the stove and what you intend on doing with the it.
Find the ball valve on the flexs connection, a metal hose usually found behind the gas oven. The ball valve is usually on the very end of the flexs connection, which has a handle, typically yellow or red, that must be shut off in order to shut off the entire gas oven. After this, try to turn on the stove to make sure that the valve is not passing any gas.
If trying to move the stove to another place, it is important to make sure the new place has a similar configuration and has a gas connector that fits and can be properly sealed. If the stove intended for repair is an older model gas stove, you will be able to complete the first part of turning the stove off, but not the second. Seek advice from the maker of the gas pipe if this is the case. It is important to note that it is illegal to perform gas work without a proper license.