Here is my discussion of
Dexcom Hot Sensor Change
Do not "Stop Sensor"
Insert new sensor
Remove transmitter from old sensor (I just rip off the sensor to make it quicker).
Clean transmitter face with alcohol
Insert transmitter in new sensor
Do not "Start sensor"
My general experience is that you will have a dropout consistent with a signal loss, but the new sensor will come online within a half hour and won't ask for calibration. Despite the lack of calibration, the readings are pretty darn good.
I choose to do a first calibration at "my convenience"
ps. I usually get three weeks out of a sensor. With my rate of sensor changes my sensor "hoard" should last 18 months and I now need to worry more about expired sensors.