Proposal Updates

Hello, 

I'd like to be able to make changes to a proposal after sending. Say I send a proposal but I want to make a change to a price, I can do so before they've viewed it. Almost like they're viewing a landing page I guess? I was just having some second thoughts on a price I quoted, but from looking at the structure, it seems there is no way to change it even though the client hasn't viewed it yet. That capability would be nice. I'm going to roll with the quoted pricing since I don't have a choice now, but I'd like in the future to have this ability. 

Thanks,

Sharon