How to save the parent model from children?

Question

I have a parent route. it has the model which is used by all child routes. when i consume the parent model from one of child ( first page ) I am updating the model like this:

selectedList : Ember.computed.map('model.selectedTrans', function(card,index){
        return Ember.Object.create({
            count : index + 1, //adding new info
            countSize : this.get('model.selectedTrans').length,
            durations:[6,12],
            duration:12 //adding new info
        })
    }),

after this, I am taking the user to next page ( sibling of updated page ), but when i try to fetch the updated info, I am not able to get it. the updated info not at all available there is next page.

what is the issue here? or how to update the local model? ( I am not sending or fetching from server )