Under South African law, the seller's death before the property is transferred and registered in the purchaser's name does not result in the cancellation of the agreement of sale. The agreement of sale remains valid and enforceable if it was validly concluded before the seller’s passing. 

Any transfer documents which may have been signed by the purchaser prior to his/her death, however, become invalid and cannot be used to affect registration of the transfer of the property. 

To proceed with the transfer in accordance with the deed of sale, the seller’s deceased estate will first have to be reported to the Master of the High Court, and an executor will have to be appointed to administer his estate. The appointment of an executor is a crucial step in the process, as no further progress can be made on transferring the property until one has been appointed.

Once an executor has been appointed, the executor effectively steps into the shoes of the deceased seller. This means that the executor will be responsible for performing the deceased’s obligations under the sales agreement, including signing the transfer documents to affect the transfer of the property into the purchaser's name. 
It should, however, be noted that after the executor has signed the necessary transfer documents, an additional procedural step must be followed by the conveyancers handling the transfer. 

After the executor has signed the power of attorney authorising the transfer of the property, the conveyancers will have to obtain the Master of the High Court’s consent to proceed with the transfer.

This entails submitting the power of attorney, the deed of sale, and the prescribed application form to the Master for consideration. If the Master is satisfied that all conditions of the deed of sale have been complied with, he will endorse his consent to the transfer on the power of attorney, and the endorsed power of attorney will be returned to the conveyancers attending to the transfer. 

After receiving the endorsed power of attorney, the conveyancers will be able to proceed with the usual steps to finalise the transfer of the property into the purchaser's name.

In conclusion, while the death of a seller inevitably introduces delays and additional administrative requirements, it does not invalidate an agreement of sale. The transaction remains legally binding, with the appointed executor assuming the seller’s role and ensuring that the obligations under the agreement are fulfilled.

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