Classic- Import metadata to update Period names?

Hi everyone,

We are on 11.1.2.4 and testing out a daily Planning application. It is a classic application and we have the 366 base periods to be set by day. We're trying to update the incremental Period members to be Jan 1, Jan 2, Jan 3, etc.

The Import Metadata function is not working, it thinks it is trying to add base Period members (even though we added an Operation column with Update value). Choosing to delete the members before import option does not work either since it is base Periods. We just want to update the names of these Periods.

Outside of editing 1 by 1, or back-end SQL statements, is there a way to accomplish this? We could not find any option or file setting to get it to update the period names.