Swiss and UA will have different PNRs. As noted, you can (potentially) upgrade on those fares only if on UA metal. Star Alliance upgrades are rare and then only on certain expensive economy fares, and if upgrade space is available, which it usually isn't (I have never found it). But you can also upgrade on UA for miles only if R class is available, which it often is not, and if you waitlist online, it is just luck if any comes open. You can also monitor the price on Yapta and if the regular business fare drops at any point, you can just buy up for cash.