To include parents as hosts on the invitation, you could use wording such as:

Mr. Michael Alvin Barrett and Mrs. Karie Lynn Boehrns-Barrett,
together with their parents
Mr. and Mrs. Alvin Barrett and Ms. Cynthia Ann Boehrns
cordially invite you to attend a
renewal of vows
at seven o’clock in the evening
Grace Church
1001 Smith Avenue
Nashville, Tennessee 00001

A more personal option would be:

We learn to experience love in our families and our friends…
this unity of new love will not be complete until you share with us this special day

We request the honor of your 
presence at the reaffirmation of wedding vows of our daughter
Karie Lynn
Michael Alvin
son of Celeste and Edward Barrett
Saturday, June 23, 2012
at 5:00 p.m.
Grand Manse
Alexander, Nevada

Anna and John Boehrns

For a more traditional style of invitation, the following would also be appropriate:

The honour of your presence is requested
at the renewal of the wedding vows of
Mr. and Mrs. Michael Alvin Barrett
Saturday, the seventh of June
at six o’clock
First Presbyterian Church
1616 Alexander Street
Hometown, Nebraska
Please join us immediately afterwards
for a reception
Grand Mansion
3456 Spectacular Place
Hometown, Nebraska