Good morning tax experts!

I just found out I need to amend my client's return because Form 3115. On Form 3115, I didn't check "yes" but checked "no" on box 3 Part I (page 1), and didn't check "No" on Schedule E on questions 1 to 4 (page 8). The return accepted on 1/29/2025 for federal, AZ and OK states. By the way, Form 3115 has not mailed to IRS yet. Questions:

1. Is ok for me to amend the return now while my client is waiting for the refund? Today is 2/8/2025, which is 10 days from accepted day.

2. Form 3115 is required to mail to the IRS, correct? if so, is there any form or document need to be mailed with Form 3115?

3. When is the timeframe to mail to the IRS? within 3 business day after e-file? or any time within the filing year?

Thank you for your help tax experts!