Ibn Ezra on Leviticus 27:20

ואם מכר. טעמו או מכר, ולא יוכל בעל שדה אחוזה שיגאלנו בעבור שמכרו לה׳‎: OR IF HE HAVE SOLD. Ve-im makhar means, or if he have sold.⁶⁸Not “and if he hath sold”. In other words, the vav of ve-im (or if) is not to be rendered as and. The owner of the field cannot redeem the field because he sold it. It is to be holy to God.⁶⁹After the year of the Jubilee.