How to make a held note's pitch descend?

Hi, I'm trying to make an instrument (for now it's violas but I might change it) have its pitch descend as it's held. I did it with bends in musescore 3, but now it's requiring that the bend end on an actual note. This causes the playback to make a weird janky sound rather than just fading out nicely. What can I do to fix this?