Income based payment plan for parent plus loan

I have a parent plus loan of about 133K. The loan is on my name. I am retired. We are on on my social security income and my wife’s income of 50K. I was thinking of moving to an income based payment plan for this loan based on my social security income alone. As a first step, I have to consolidate the loan. Since we have been filing a joint return all along, the student loan site wants my wife also to cosign the the loan and I understand that if anything were to happen to me. she will become responsible to repay the loan. I want to avoid that. To do that , starting from this year, can I start filing independently and then apply for this program. What will be the downside to that? Is that reversible?