You cannot change the primary field to a different field. You can only change the definition of the individual fields and move values around to match.

You will need a temporary field to hold values as you move them around to avoid loosing data. You also need a temporary name for your primary field as two fields cannot have the same name at the same time.

Option 1

1. Rename the primary field to a temporary name, such as PrimaryTemp.
2. Create a new field named Title.
3. Copy all the values from the primary field PrimaryTemp to the new Title field. You can do this as a single copy/paste by selecting the column.
4. Copy all the values from the Artist field to PrimaryTemp.
5. Delete the original Artist field.
6. Rename the PrimaryTemp field to Artist.

Option 2

This method uses temporary formulas to avoid copy/paste errors.

1. Rename the primary field to a temporary name, such as PrimaryTemp.
2. Create a new field named Title as a formula field with the formula {Title}. Wait until the titles appear in all the records in both columns.
3. Edit the new Title field type, to change it from Formula to Single line text. This will convert the titles to regular strings.
4. Edit the primary field, making it a formula field with the formula {Artist}. Wait until the artists appear in all the records in both columns.
5. Edit the primary field, changing it back to type Single line text. This will convert the artists to regular strings.
6. Delete the Artist field, and rename the primary field to Artist.

Option 3

Another option is to have “Title” and “Artist” as regular fields in your table. Then convert your primary field to a formula. This method is the most flexible, making it easy to change the primary field on the fly.

1. Rename the primary field to a new name, such as Album or Painting.
2. Create a new field named Title and copy the values from the primary field Title to it, using either regular copy/paste or the formula method described above.
3. Edit the primary field, changing it to a formula with the formula. For example, {Artist} & ' - ' {Title}.

Tips:

You can rename or edit the field type of any field by clicking the small triangle to the right of the field name. Select “Customize field type” or “Rename field” from the menu. (Both menu options do the same thing).

Make sure that you aren’t using any filters and can see all the records when you copy value around! If you copy/paste when viewing only some records, the values that you don’t see won’t be copied/pasted.