Is there any way to modify (change instance type) of my Windows Reserved EC2 Instance?

I have a t2.medium Windows based reserved instance. Now I want to upgrade it to t2.Large. As far as i have checked one can only change instance type of Linux reserved instances. Is there any way i can do it for my Windows based reserved instance?

When i go to submit modification request it doesn't display any option to change instance type. Only Availability Zone modification is allowed.

Thanks