Adding new donor to form 10 BD after due date

1. File a revised Form 10BD: you can file a revised Form 10BD with the updated information, including the new donor. 
2. Use the same acknowledgement number: You can use the same acknowledgement number that was generated when you filed the original Form 10BD.
3. Mention the reson for revision: In the revised Form 10BD, you should mention the reason for revision, which in this case is the addition of a new donor. 
4. Submit the revised form: Once you have completed the revised Form 10BD, submit it to the relevant authorities. 

Hi, I have done this but in the revised form, if we are adding a new donor, what should be the acknowledgment number? The acknowledgement number of the original filing does not work.

For adding new names in Form 10BD you have to file a new form as original not revised, since the donors are being added first time and not being revised any existing donors details, Late fees may apply for filing after due date.