Hi,
The fan is part of the thermal module. It is one complete assembly.
Here's the [https://download.lenovo.com/consumer/mobiles_pub/yoga_c740_series_hmm.pdf|hardware maintenance manual] for the laptop. Go to p.31 to view the procedure to remove the thermal module.
The part number for the module is ''5H40S19963.'' Search online using the ''part number only'' to find suppliers that suit you best.