Mongo - how to rename object keys?

Question

MongoDB

I have a selection of objects

var pages = db.getCollection('blocks_copy')
.find({Type: 'page', Folder: {$in : ['bakeries/rosenborg/pages', 'bakeries/brogylen/pages']}, 'blocks': { $exists: true }}).toArray()
printjson(pages)

For objects with this type, I'm interested in the blocks field and I need to rename all the keys that this field contains

pages.forEach(function(e){
    var changedNames = Object.keys(e.blocks).map(function(e){return `Rosenborg${e}`})
    printjson(changedNames)  
})

Okay, I have an array with new key values, but I don’t understand how to update the database in this case and what method to use for this.

Thanks for the help!