Hello frineds !
I recently got a cheap ticket ex.BUD to SEA last weekend.(I-CLASS)
But I realized I need Inbound flight modification so try to do at Delta.com but not poss due system reason.
So I contact a local Delta center but what I heard was a tremendous price gap.

What I know from common sense is that when before departure and want to change I/B ,
fare is retrieved from the ticket issue date and tax/YQ/fee needs to be adjusted to new ticketing date.

But Delta said, regardless of changing O/B or I/B, when you want to change b4 dep, the fare is adjusted to new ticketing date.

Is Delta agent wrong or am I wrong??
Do you have any experience? please share. Thank you.