if you change jobs), you may need to contact your mortgage broker or lender to ensure that your mortgage is in principle still valid and, if necessary, renew the application. To get a mortgage in principle, the lender will usually ask you for basic information that is only used to assess the affordability of your mortgage. This makes a mortgage in principle a little less reliable, because if the lender does a full search for mortgage data before making you a mortgage offer, they will check in more detail your finances, credit history and the property you want to buy. You may find that your mortgage is in principle becoming an unreliable factor for your ability to get a mortgage or not. You do not need to go through the entire application process to get an agreement in principle.