Consular officers are authorized to grant to an alien the immediate relative or preference status accorded in a petition approved in the alien's behalf upon receipt of the approved petition or official notification of its approval. The status shall be granted for the period authorized by law or regulation. The approval of a petition does not relieve the alien of the burden of establishing to the satisfaction of the consular officer that the alien is eligible in all respects to receive a visa.
22 C.F.R. §42.41