ALTER TABLE ENVIO_AVISO ALTER COLUMN nombreReceptor varchar(255);

ALTER TABLE RECEPTOR_AVISO add documentoelectronico2 bigint;

UPDATE RECEPTOR_AVISO SET documentoelectronico2=documentoelectronico;

alter table RECEPTOR_AVISO drop column documentoelectronico;

EXEC sp_rename 'dbo.RECEPTOR_AVISO.documentoelectronico2', 'documentoelectronico', 'COLUMN';