I have a pet I am trying to adopt out and I have found a user who is interested, but there's a question about pet slots. They currently have 6 pets, but only 5 slots. They're thinking that if they get rid of the 6th pet, they'll still only be able to have 5 pets and that 6th pet's slot won't become available and will instead disappear. I just wanted to check to see if that is indeed correct and/or if there's a way to make it work.

They need a GA to gain access to the 6th pet

in other words, the slot will still be there but they can't put a pet in it unless they have a GA

They don't need to get rid of their 6th pet at all if they get a GA. Getting a GA gives you an extra 5 pet slots. :3