Professor Changed Syllabus

So long story short, the final exam date is nearing and I went on the syllabus to check when it would be (throughout the entire semester or was clearly stated that it would be online.) To my surprise I go to the syllabus and read that now it says “Final exam 20% In-class.” I made travel plans based on the syllabus, now I don’t know what I should do. Is he in the right to do this?