Is this a lot of work for a travel consultant?

I have a holiday booking and want to upgrade our room BUT before I do this I want to know if it's a lot of work for the travel consultant to do? In other words will it cause her a hassle or it it generally a simple process?

Not at all, just takes a phone call or a few emails, it's their job to keep customers happy. They shouldn't have to complain, plus as you are upgrading, you'll be giving their company more money, therefore more commission.