To Delete a Cell from a Custom Table:

Help > Authoring > Working with Tables > Table Editing > Inserting and Deleting Cells > To Delete a Cell from a Custom Table:

1. To delete a cell, place the cursor in a cell choose Table > Delete Cells. The cell in the row containing the cursor is deleted and the adjacent cells move in the direction specified.

If more than one cell is selected, the selected cells are deleted.