Question About Mortgage Transfer

[William Houstian]

I recently came across this flowchart of a call with a potential seller and I had a question about this particular section in it regarding the transfer of a mortgage. In the scenario, the seller's house currently has a mortgage on it, and they are not willing to allow me (the buyer) to take over the note. This results in the clarification question "You won't sell your house unless you get full asking price?" My question is, where does this conclusion get drawn? Why does them not wanting the buyer to take over payments of the mortgage result in the assumption that they are asking full price? If they did allow me to take over the note, wouldn't the price be the same (whatever the balance on the mortgage is)? Thanks, I was just confused by this and by the process of transferring a mortgage in general, and would greatly appreciate if somebody could explain it.