I have a couple of tickets booked by my travel agent in a refundable fare class. I want to re-issue these in R class after ticketing, paying the add/collect out of my pocket.

They show up on my online CO profile.

I see a link to change flights - it is possible to use this function to 'reissue' the ticket in F (R class) while keeping the same flights, or would I need to call reservations?