Switching Mainstage sound library from internal to external SSD

I have Logic Pro and Mainstage on a desktop and a laptop (desktop is on the latest OS, laptop is a 2014 on OS 11.6.1). I keep the sound library for my desktop on an external SSD and would like use it with my laptop as well. My laptop refuses to use it, but it does recognize there is a sound library on it. My laptop doesn't have the space to store the full library on the internal SSD, so I really need it to use the external library. So far I am unable to do the "relocate sound library" function, because the external drive already has a sound library on it it's greyed out. How do I get mainstage to use that library instead of the internal?

[Re-Titled by Moderator]

Original Title: How do I get Mainstage to switch from the sound library download on the SSD to a different sound library on an external SSD?