If changes have been made and the reference model needs to be reloaded, the layer icon for the parent layer of the model will display a red exclamation mark. If this symbol is not present, no changes have been made by other users. 
Pop-up | Reload Model (Layers window) |
The Reload Model command is used to update the model with any changes that may have been saved to the source file since the model was opened. This could happen if more than one user has the same reference model open in different instances of the application.
If changes have been made and the reference model needs to be reloaded, the layer icon for the parent layer of the model will display a red exclamation mark. If this symbol is not present, no changes have been made by other users.
Procedure
1. Select a layer of the desired model in the Layers window.
2. Select the Reload Model command.
The reference model is reopened, applying any changes that were saved to the file by the other user.