Taken from new website www.inthespiritofcana.org
2.6.9 Convalidation (Re-Validation/“Blessing the Marriage”) ****
There’s no right word for this phenomenon. Sometimes it’s called a convalidation; sometimes a revalidation; and couples usually call it “getting their marriage blessed.”
Most commonly, the situation is that a couple has entered into a civil union, and they now wish to exchange consent in the Church. Canonically, the Church does not recognize their prior exchange of consent, but there is
some sort of commitment which they made to each other, and some sort of moral responsibilities which flow from that commitment.
Since according to the Church the couple is exchanging consent for the first time, all of the requirements for entering the Sacrament of Matrimony must be fulfilled. The couple must exchange consent anew (and not simply renew consent that was previously given), and they must have the proper knowledge, intention, and capacity for doing so.
For those raised in the Catholic Church, there may be an understanding that their “real” marriage is the one that takes place in the Church. For non-Catholics (whose churches require no particular form for marriage), the requirement for a new act of consent may not be obvious. In either case, the pastoral minister should explain this in detail.
If the other party does not see a need to give their consent again, and is adamant that their former consent was good enough, then it might be better to seek a
sanatio in radice, rather than try to convalidate the marriage. (A
sanatio in radice is a retroactive convalidation of the marriage, which does not require a new act of consent.) If this seems the preferable way to handle the situation, contact the Office for Canonical Services to obtain details about this.