(I'm assuming you're talking about the hood / vent / exhaust fan instead of the internal magnetron cooling fan).
The part # SMV-260UA-C will not be enough to go on, as there at least 3 variations on that number shown at Samsung parts.
These microwaves are made by Samsung, but you'd need the GE part number to replace the whole thing. They don't sell the blades separately.
The part # for the "ventilation motor" is WB26X10042 and you can find it for $97.11 here, which is about fifty dollars less than direct from GE.
I may have available a replacement flan blade off a used unit. If you'll send me the dimensions, I'll check. I need the length of the fan blade, the diameter, and the inside diameter / shaft size, and whether the shaft is round or "D" shaped.
Please feel free to contact me directly.We're happy to help you and we'd appreciate your
thoughtful rating of our answer.
William E. Miller, AS-EET