First, return the license if it has been temporarily checked out from the network. Connect the client computer to the server that hosts the License Manager. Use the command Help > Floating License > Check In a Floating License. This restores the number of concurrent users the server allows.
Then, use the Windows Settings > Apps and Features to uninstall ExtendSim.
Then delete the two folders: Documents\ExtendSim and Program Files\ExtendSim.