NASA CO

Ok, this may be considered a silly question by all of you incredibly smart people (see how flattery works). I have a cost plus contract that at the time it was awarded in late 2019 it was for $385M. Now because of COVID and cost increases due to materials and inefficiencies, etc., my project manager doesn't want to spend the next 3-4 years having to deal with settling overruns. His solution is to increase the contract value up to what the contractor is estimating at time of contract completion. So now we go from $385M in value to almost $1B. I have consulted everyone i know including CO's and Lawyers and the answer is this isn't a legal contract mod. I have explained this to the PM and the contractor. The PM is still looking for a way to make this happen. Is there anyone out in WIFCON world that has worked a Cost contract that has allowed a contract value change because the original estimate (contract award value) was basically not a true cost estimate? Curious CO wants to know how it could or ant be done.