Patch Authoritative Account "alias"

We have an internal process to migrate contractors to employees or change employee username to avoid the recreation of all the identity’s access. The change is initiated from the authoritative source. When the account aggregates into SailPoint the correct UID displays, however, the “alias” remains the same. We have removed the account from SailPoint, and upon aggregation the “alias” is still the same.

Where is this attribute stored and is there an API to force it to change to the updated UID?

I don’t think alias field can be changed, its set when an identity is created in the backend, after that for any change, it remain same throughout the lifecycle of identity.

Thank you Sunny for the additional detail. Much appreciated.