Purdue declaration of engineering major:
https://engineering.purdue.edu/ENE/Academics/FirstYear/T2M
https://engineering.purdue.edu/Engr/InfoFor/CurrentStudents/enrollment-policy
Vanderbilt changing to engineering:
https://registrar.vanderbilt.edu/intra-university-transfers/
https://registrar.vanderbilt.edu/intra-university-transfers/engineering-letter.php
Cornell changing to engineering:
https://www.engineering.cornell.edu/students/undergraduate-students/advising/internal-transfer-engineering