Modifying existing animations?

*change the last letter or number in the name.

I think footman understood, considering the need to create a new name for the file with a numeric-alphabetic name. This can be done as footman suggested, by changing a letter or number. However, to ensure there are no conflicts with existing files, it's best to generate a text-based xdb file for the animation using the map editor and use a long, text-alphabetic name from this xdb file.
Important: the imported animation should have the .gr2 extension removed. The file should only have this code name and no indication of the format, not even a period at the end. This might be the problem.
If necessary, the display of the format designation and the ability to change it through renaming can be enabled in Windows settings. Sometimes, by default, this is disabled to prevent users from making unwanted changes.