I'm not entirely sure about replacing the partition but for deleting p03

You could try:
/dev/mmcblk0p3:448032,,0

It starts from your p03 cylinder and replaces it with an empty partition. I'm not sure that it is right but I cannot find anything on removing partitions with sfdisk.

Then just press enter when it gets to mmcblk0p4.

You could try deleting the p02 then and repartitioning the p02.