From the Autodesk App Store:
When working with BIM models, it is very likely that a model needs to update certain grids or level names during the project’s lifetime. If the dimensions of the project are relatively large, then the task of renaming the grids and levels becomes tedious. Autodesk® Revit® plugins attempt to make tedious tasks simple and straightforward. Therefore, this tool provides a shortcut for editing the project grids. Use Grid Manager for renaming your project’s grids…
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