Hello,i would like to change the sin number but is greyout in personal info

[TurboTaxSusan]

Have you already sent your return via NETFILE? Once you NETFILE a return, you can no longer change your SIN number.

If you filed your return with the wrong SIN number, you should contact the CRA and let them know what's happened. If you are in Canada or the United States, you can call the Canada Revenue Agency (CRA) at 1-800-959-8281. If you are elsewhere you can call 613-940-8495. This page has more ways to contact the CRA: https://www.canada.ca/en/revenue-agency/corporate/contact-information/telephone-numbers.html