Why can't I replace a field in a mongoose document?

vk_account.save(function(err, vk_account) {
 if(err) return cb(err, null);
 vk_account.Sources = updated_sources;
 vk_account.settings = account_setting;
 cb(null, vk_account);

In vk_account.settings(Should be an Array in terms of schema, mongoose), I assign account_setting(Object). As a result, in vk_account.settings and absolutely nothing changes.
I don't want to go against the system schema, mongoose, I have this document save not going, I just want to replace one field with another, and to give the client the result.
June 5th 19 at 21:15

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