Unsoldering SMD components can be very frustrating, time consuming and a disaster. Here is a trick i've found in a electronic magazine of which i forgot the name.
All you need is a piece of enameled copper wire of about 0.2 to 0.3 mm in diameter.
Take a length of this wire and slide it under the pins of the circuit you want to unsolder. Attach one end firmly,( because you will have to pull on it ) in soldering it on a large pad close to the circuit.
Pull firmly on the free end of the wire so it leants again the first pin of the circuit. Do that while keeping the wire as close as possible to the printed board.
Heat the first pin, the enamelled wire should slip under the pin and raise it from the board.
Repeat this procedure for each pin, taking care not to break them. Double your attention for the last one, the wire being stopped by nothing.
Make some tests on a defective board before applying this method to a board you want to repair.
The smallest SMD components can't be unsoldered this way, you can't even slide a wire under the pins !
Let me know if this could help you and/or if you have a better method.