As I said abdominal wind is one of the major cause of displaced navel. So you need to control over abdominal wind , if you able to control it then navel can be managed.
1- avoid bad food and control over quantity and quality of food.
2- do walk for half an hour.
3- do paean mukt asana so many times before meals.
4- do anulom - violam pranayama for 10 to 15 minutes at a stretch.
5- do abdominal breathing for 10 to 15 times after meal.
Thanks & with regards
Yogi anoop