Change name of part after mid-staff instrument change

I'm working on a score for string quintet with a section 'con sordino'. In order to affect playback and mp3 export, I added 'change instrument' and changed the sound as needed in the mixer.

However, when I add 'change instrument', it changed the part name for that section, as well. I realise this is by design, but I'm not able to modify the changed names. For example, at the beginning of the score, I have the part names set as 'Violin I', 'Violin II', 'Viola', 'Cello', 'Bass'. After adding the 'change instrument', from that point forward, the part names are 'Violin', 'Violin', 'Viola', 'Violoncello', 'Contrabass'.

Is there some way to change these 'new' part names? (When I go to 'stave/part properties', it only gives me options for the first section, not options for after the instrument change.)