@June228 Your post is really unclear. Do you mean you are taking over for your friend as co-host and the current property manager won't pass booking info on to you?
@June228 It will depend on the contract between your friend and the local Airbnb management company.
If you don't actually have a contract, or the contract is silent, then it is actually in the interests of the management company to allow bookings to transfer or they will have to cancel all the bookings.
Whilst not clear from your post, if the calendar looks fully booked it is likely that the company has blocked all the dates to stop people booking.