Nothing will need changing, many new cars sit for months at a time, we still have access to some new and unused BMW’s registered June 2019.
Before you ask the warranty starts from registration date but do check the service countdown is reset if it’s had an early PDI.
Some larger fleet dealers are delivering cars but most smaller retail outlets have furloughed staff and would need individual people to do the following to make it happen, PDI, Valet, Invoice, Register / RFL, Hans over.
In most cases main dealers are just taking holding deposits on used cars rather than delivering them.