Dress alterations will ruin dress x

I get to the point I have had my dress for a while now size 30 I'm a size 20 don't ask well had my appointment with seamstress she has said if I go all the way down to size 20 I will lose most of the pattern on the top of of dress which is my favourite bit of it don't want another dress cos I love this one alterations already cost more than my dress don't want to order a new one because the one I have will be harder to get rid of because of size don't know what to do X suggestions please 😭