I don't know another way to modify Element IDs this way.
The one way I can think of is to use Element Properties.
Create an Element Property that you would use instead of the Element ID in Labels and Schedules.
You can then Export this Property using the
"File>Interoperability>Classifications and Properties>Export Property Values from Schedule" menu command to export them to Excel.
Then modify the values in Excel, which I think you will be able to do.
Then import the modified values using the "File>Interoperability>Classifications and Properties>Import Property Values into Elements"
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