See "What do I do when I am assigned a social security number (SSN)?" at the link below:
Since the IRS local offices are closed for COVID-19, you can't request combining the filed tax records in person. However, I just mailed off the paperwork to the IRS to combine the ITIN and SSN tax records yesterday.
Conceivably the IRS would automatically switch the ITIN with SSN. Afterwards the “Get My Payment” IRS website would allow you to enter your information. Right now both of us get "Payment Status Not Available" when trying to use "Get My Payment".