Unable to switch from GPT-4o conversation to GPT-o1

It seems like I could switch from an o1 conversation to gpt-4o conversation, but not the other way around. Why?

I understand the online browsing ability is limited on o1 models. But I am supposed to just use the 4o conversation cache (processed, offline context) onto a more thorough gpt-o1 discussion to think them through, right?

Same hereā€¦I started out a new chat on the Android app with o-1 and then switched to 4o and now the option to switch to o-1 and o-1 preview is disabled.