My six year old daughter has got umbilical hernia which is 6 mm out of her navel. how can i treat it without surgery?

Not likely: Most umbilical hernias that are present in babies will resolve by themselves by 3 years old. Those that are still present at that age are less likely to close on their own without surgery. The surgery is very quick and effective.

? hernia or "outie"?: If it is truly a hernia, with bowel contents pushed out between the abdominal muscles, it would require surgical correction.If she simply has some tissue pushing out, and not a hernia sac, it is not worthy of worry but is unlikely to change.Your measurements suggest this is just an "outie"not a true hernia. It would be unlike a hernia in not a potential risk, but only surgery would change it.