Form 10IEA for re-entering new regime

Revoking Form 10IEA before filing ITR:

As per the income-tax act, 1961, there is no direct provision to revoke Form 10IEA once it is filed. However, you can still file your ITR under the old regime, and the filed Form 10IEA will not be considered until the ITR  is filed under the new regime. 

Filing ITR under the old regime withut acknowledging 10IEA: 

If you files your ITR under the old regime without acknowledging Form 10IEA , it will not be considered an invalid return. You can proceed with filing your ITR under the old regime, and the tax authorities will process it accordingly. 

Tried filing but it is saying cant upload without giving 10IEA details. So is it like we do not have any option of filing under old regime.

To re-enter the new tax regime after a previous opt-out, business or professional income taxpayers file Form 10IEA before the due date of their ITR, which is July 31, 2026 for non-audit cases. One thing to be clear about before you do this: for taxpayers with business or professional income, this re-entry is the final switch. Once you go back to the new regime via Form 10IEA, the old tax regime is no longer available to you in any future year. If you are a salaried employee with no business income, none of this applies since you can choose your regime fresh each year directly on the ITR form without filing any separate declaration.