On BCP page 323, the rubric at the bottom of the page gives us direction:

But if a man, either by reason of sickness, or for want of warning in due time to the Minister, or by any other just impediment, do not receive the Sacrament of Christ’s Body and Blood, the Minister shall instruct him, that if he do truly repent him of his sins, and steadfastly believe that Jesus Christ hath suffered death upon the Cross for him, and shed his Blood for his redemption, earnestly remembering the benefits he hath thereby, and giving him hearty thanks therefor, he doth eat and drink the Body and Blood of our Savior Christ profitably to his soul’s health, although he do not receive the Sacrament with his mouth.