extents management

 I have a table that have storage I set for max extents to 2100, right now the number of extents used is about 60% used of the max extents. I know I could increase the next extent size and then increase the number for max extents so that the percentage will be less than 60%. Or, I could do export and import to recreate the table with less extents. However, since this is a production table, I'd rather not to use export and import. Because this way the user will have a period of time cannot access the table. Is there any