Which design pattern better fits this case?

Using C#, I need to serialize different types of objects filled with data to JSON string. I need some sort of method SerializeObject(T obj) so I can provide an object. The type of object can be different. For example, I have the following POCO-objects:

class Transfer
{
    public decimal Amount { get; set; }
}

class RootTransfer
{
    public int Id { get; set; }
    public List<Transfer> PaymentInfo { get; set; }
}

and

class Account
{
    public decimal Amount { get; set; }
}

class RootAccount
{
    public int Id { get; set; }
    public List<Account> Accounts { get; set; }
}

Using this SerializeObject(transfer), I want to get something like this in return:

new RootTransfer
{
    PaymentInfo = new List<Transfer>
    {
        transfer as Transfer
    }
};

Is it an abstract factory? Or repository? Please advise.