Insurance Claim submission

Hi there! I submitted an insurance claim for a client with two different dates of service. Unfortunately, one of those dates of service was denied and the other was paid. The client would like me to now submit to a different insurance for the denied date of service, because they believe they made an error. They think they were not insured by the first insurance but had a different insurance provider at that time of service. Is there a way to split a claim or detach a date of service from a claim in order to submit that date of service to a different insurer?