You can visit your nearest enrollment centre to get the details of your linked mobile number changed.
You can read about the process in details here:
- https://uidai.gov.in/my-aadhaar/about-your-aadhaar/updating-data-on-aadhaar.html
- https://www.paisabazaar.com/aadhar-card/aadhaar-card-update-correction/