HOW TO DEVELOP A REVISED BASELINE SCHEDULE, LAST UPDATE SCHEDULE?

Dear Professional,

Hope every one is fine.

Let me first put up my case, I have updated schedule up to August 2017 (Schedule % 17.5 & Performance % 15.2) at that time.I received an approved EOT of 40 days from a consultant I revised my schedule with respect to fast track/crash method technique to overcome the delays.
Now the issue is that when I go to remove the old baseline to assign the new one(copy of revised schedule) at that time my schedule% & performance % value drop down to zero by removing the (Project Baseline).

I normal conditions our Performance% complete will be now our schedule % complete after revising the schedule for future tracking & monitoring.

Your earliest response is required

Regards,
Abubakar