@LMorian5, contact account/payment support at https://support.roku.com/contactus, but I think the only way to change the date is to cancel the auto-renew on the subscription and subscribe again on the day you want your payment to occur. Every subscription you have through Roku will have its own date. I doubt there's a way to have them all occur on the same date other than always starting a subscription on the desired date, but support should know more than me.
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.