File > Assign Offline File

References the edits from the file you select and applies them to the reference node selected in the Reference Editor. Maya applies edits by matching each nodename.attribute in the edit file to the file its being applied to.

For example, you can export a reference edit for pSphere1.translateX in the scene sphere.ma. This edit is saved in the reference file as <main>:sphere_pSphere1.translateX. You can then apply this edit to the scene ball.ma so that ball:pSphere1.translateX is edited.

File > Assign Offline File >

General Options

Apply via: Allows you to apply edits as either a referenced edit or import the edit straight into your scene. Imported edits are baked into the main scene and cannot be unloaded like referenced edits.
Assign offline edits to main scene: If turned on, the offline edits are stored in the main scene. Otherwise, the edits are stored as a file reference.
File type: Select from the drop-down list the file type you are importing. If you aren’t sure what type of file you are applying, you can select Best Guess.

Depending on the file type you select, various file type specific options may be displayed.

Name Clash Options

Use namespaces: If turned on, namespaces from the offline file are preserved in the current scene.
Resolve all nodes with: When you import a scene into another scene, naming conflicts occur if the nodes share the same name and parent nodes.

To resolve these naming conflicts, you can rename only nodes with the same name and parents (clashing nodes) or you can rename all nodes. You specify whether to use the filename as the prefix (the default) or to create a prefix string.