Is an additional saving throw required if the corresponding ability score changes?

Question

Examples:

1. A fighter is fighting a dragon. The dragon uses its Frightful Presence action. The fighter, who has a Wisdom score of 15, succeeds on the DC 16 Wisdom saving throw. It is then the party warlock's turn, and she decides to polymorph the fighter into a giant hairy ape with a Wisdom score of 12.

2. Alternately: The same fighter is fighting another dragon. This time he fails the save against its Frightful Presence, and is frightened for 1 minute. During that minute, the cleric casts a spell to increase the fighter's Wisdom score to 17.

In either example, will the fighter now need to make another DC 16 Wisdom save, since his Wisdom score has changed?

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The following questions were similar, but did not answer mine:

• Is there a general rule for which saving throws you can repeat?

• Does Calm Emotions still allow a saving throw?

Answer 1

You make a saving throw when instructed to, using whatever your bonus is at the time.

The typical dragon's Frightful Presence feature says:

Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Now, Frightful Presence is an action, so when the dragon uses this action, you do what the ability says. In this case, an affected creature must:

succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute.

The saving throw happens when the dragon uses the Frightful Presence action, and an affected creature uses whatever their save bonus is at that exact moment. If the creature's ability score or save bonus changes, it does not trigger another saving throw, because an affected creature only makes a saving throw when the Frightful Presence ability says they must make a saving throw. In this case, if they fail the initial saving throw, they do not make another one until:

the end of each of its turns

And they would use whatever their wisdom score happens to be at that moment.