Oh. OK. I thought you couldn’t do that, but I found the following topic (older), that provides instructions you might try.
However, in another post on reddit Brave support reply says you can’t. So, conflicting information.
You can try the first topic and see if it works. If it doesn’t, the second applies. AFAIK once you link a Rewards wallet id to a custodial provider account, it is permanently linked to that account. If you try to link the Brave wallet id to a different Uphold account, you will get an error message.
Please post an update on what you tried and whether it worked or not. Also, if you receive an error message, can you post that also? It will help other community members (and me) pin down the correct answer.
Edit: Just noticed that first post was for a creator account. I do not know if creator accounts work differently or the same as Rewards. You can still try and see if it works or what messages you receive if it doesn’t.