How should I phrase a résumé if I have an uncertain degree plan?
Facing an uncertain graduate date is a common issue, particularly for many Ph.D. students who aren't sure exactly when they are going to defend.  The thing that you want in your C.V. is to communicate as clearly as possible what are your skills and time of availability to the people considering taking you on for your next career stage after graduation.  Thus, put your current best estimate in; if you want to indicate an option to join a position earlier, put that in as well as an option.