If the external instructor for disability awareness training changes, do I need to re-verify their qualifications?

Hello. I am in charge of mandatory legal training at a company with approximately 200 employees.
We plan to conduct workplace disability awareness training this year as a group session organized by an external training institution. However, we were informed that the instructor originally proposed at the time of the contract has been changed due to scheduling conflicts. The institution assured us that the training will proceed with the same curriculum and materials, but we have not yet been able to verify the new instructor's qualifications or affiliation with the institution.
We are currently reviewing a plan to obtain the changed instructor's name, professional instructor qualifications or required training history, employment or appointment relationship with the educational institution, and actual training dates again and attach them to the contract documents. We are also considering which version of the instructor data should be kept as final proof in the event that sudden replacement instructors are repeatedly deployed.
If an external instructor is changed, should the training manager re-verify their qualifications? I would like to know what reference date should be used to store the instructor change confirmation, proof of qualification, training log, and list of trainees.