Ah now you're talking about changing airport
names rather then their IATA codes.
If they ever did rename Dulles to Trump it's very unlikely they would change the IATA code from DUL to DJT as that would generate significant international pushback not necessairly because of the name but because of the impact in the code.
The proposed Bill doesnt mention that. Though I note that not even the GOP reps in VA have signed up and nor have the uber trump sycophants like MTG who would normally be all over this sort of thing
https://www.congress.gov/bill/119th-...691/cosponsors