If you are a pastor or staff member at a parish, then you will likely be approached by couples who have been civilly married, and would now like to be married in the Church. They are looking for a convalidation.
"The Church very much wants to assist these couples who later want to enter into valid Catholic marriage, and it offers them pastoral and spiritual support as they need it. When these couples are ready and free to do so, they celebrate what is called a convalidation, from the Latin word meaning “to firm up” or “to strengthen.”
It is important to realize that a convalidation is not merely a renewal of vows made previously but is a new act of consent by each spouse. This new act of consent is essential to marriage, and the words that the couple expresses are the outward sign of the gift of self that they exchange. This convalidation of marriage may be celebrated within Mass or outside of Mass, again depending on the particular situation of the couple. If both are Catholic, it is fitting that the convalidation be celebrated within Mass. If one spouse is not, it is preferable that it be celebrated outside of Mass." - from Together for Life Online
READ HERE for a helpful article on How the Church Convalidates Civil Marriages