I think if he’s good in the new system, you work to give him a reasonable 1 to 2 year extension to buy yourself a little more bridge QB time. If he’s bad, you cut him with a 6/1 designation and go all-in on a new passer in the draft or next year’s free agency/trade period.
What’s defined as “good” or “bad” will need to be evaluated by the team, in conjunction with the team results.