Need Advice On Cutting 2 PVC Cleanouts

Had an old wood deck demoed today in preparation for a new concrete patio. When deck was removed it was discovered that we have 2 PVC pipe cleanouts sticking up about 24″ out of the ground. We’d like to still access these but would prefer that they are flush with the new concrete patio for obvious aesthetic reasons.

Will it be as simple as just cutting them shorter with a saw? Should we cut before or after the new patio is poured? Concrete guy said we should surround the pipes with foam as well to protect from concrete.

Any advice or tips would be greatly appreciated.