Classical album sets not always in correct CD order

If an album (say an opera) appears on Roon after ripping, with the CDs appearing the wrong way round - ie Act II (on disc 2) followed by Act I (even though that is disc 1) how can you swap them round to place in the correct sequence. Every time I go into disc edit, the tracks become messed up so I have to exit and leave them as originally ripped.