UT Cockerell School admittance ? Admitted to different Major than applied for?

Son accepted into Cockerel School of Engineering but didn’t get his 1st or 2nd choice (Chemical, Aerospace Engineering) but instead got Accepted into Petroleum Engineering? Anyone get accepted into their chosen school but not their chosen Major? Anyone know if there is a future option to transfer? Top 3%, (class of 1440)
SAT 1400. (790 math) Varsity Sports plus other clubs, community service

A friend just went through the same process. He was told it was virtually impossible to change majors… I think they require a 4.0-ish GPA and even then, no guarantee. He went to A&M instead and got to select his preferred major. And currently has a 4.0! I think UT is losing out on some quality students due to their major policy.