What is the church's rubric for Mass (from the Vatican) concerning the kneeling or genuflecting while receiving Holy Eucharist? Our pastor has gotten rid of the communion rail and wants us to sing and process.
-- Kneeling in Knoxville
The General Instruction of the Roman Missal [Vatican document last revised in 1975] is quite clear about the posture for the reception of communion. I will quote you the entire paragraph about movements and postures to give you a little more context:
20. The uniformity in standing, kneeling, or sitting to be observed by all taking part is a sign of the community and the unity of the assembly; it both expresses and fosters the spiritual attitude of those taking part.
21. For the sake of uniformity in movement and posture, the people should follow the directions given during the celebration by deacon, the priest, or another minister. Unless other provision is made, at every Mass the people should stand from the beginning of the entrance song or when the priest enters until the end of the opening prayer or collect; for the singing of the Alleluia before the gospel;while gospel is proclaimed; during the profession of faith and the general intercessions; from the prayer over the gifts to the end of the Mass, except at the places indicated later in this paragraph. They should sit during the readings before the gospel and during the responsorial psalm, for the homily and the presentation of the gifts, and, if this seems helpful, during the period of silence after communion. They should kneel at the consecration unless prevented by the lack of space, the number of people present, or some other good reason. But it is up to the conference of bishops to adapt the actions and postures described in the Order of the Roman Mass to the customs of the people. But the conference must make sure such adaptations correspond to the meaning and character of each part of the celebration.
In the United States, at its meeting in November 1969, the National Conference of Catholic Bishops voted that in general, the directives of the Roman Missal concerning the posture of the congregation at Mass should be left unchanged, but that no. 21 of the General Instruction should be adapted so that the people kneel beginning after the singing or recitation of the Sanctus until after the Amen of the Eucharistic prayer, that is, before the Lord's Prayer.
244c. The communicants approach, make the proper reverence, and stand in front of the priest. Showing the host he [sic] says: The body of Christ. The communicant answers: Amen and receives the body of Christ from the priest [sic]. [TODAY SOME MINISTERS OF COMMUNION ARE LAY PEOPLE. THESE INSTRUCTIONS WERE WRITTEN IN 1969 BEFORE LAY MINISTERS OF HOLY COMMUNION.]
244d. The communicant then moves to the minister of the chalice and stands before him. The ministers says: The blood of Christ, the communicant answers: Amen, and the minister holds out the chalice with purificator.
So you can see by the text, the proper position is to be standing during communion. Except for the Eucharistic Prayer, we always imitate the posture of the priest presider. He is standing when he is giving communion. A common appeal is "reverence." We may have been taught one form of reverence as a child. Other cultures have other reverence postures that are different from the US. However, to answer your question, the Vatican document states that we are to stand while in the communion procession [singing, of course--- and that's in another section, but not part of your question], and stand while we receive communion.