Seeking Real Estate Experts for Story: What Happens If My Mortgage Is Sold?

I’m looking to interview mortgage lending experts, real estate attorneys as well as real estate faculty/professors for the following story: What happens if/when my mortgage is sold? This story will explore what home buyers can expect if/when their mortgage is sold to another lender. Below is a list of questions I’m seeking answers to. I can either conduct a phone or email interview (with the latter, please email me back full-sentence written responses that I can use as quotes). My deadline is noon central time, Wednesday, May 9. Why do mortgages often get sold from the original lender to a different lender? How often/commonly does this happen, and should a homeowner expect that it eventually will happen to them? What happens if/when an owner’s mortgage is sold/transferred? Explain how that affects the terms, balance, interest rate, credit score, etc. in any way. What should borrowers expect when their mortgage is sold (e.g., contact/bills from a new lender), and what should they do (e.g., call the new lender to ask questions)? Please provide detailed suggestions. What are some questions that borrowers should ask of the new lender to help ease their minds about the mortgage transfer/sale? Is there anything the borrower can do to prevent this sale/transfer of the mortgage, or is it completely out of their hands?