New Procedure of challan correction by banks (for physical challans):
To remedy this situation, a new Challan Correction Mechanism for physical challans has been put in place. Under this mechanism, for income tax payments made on or after 01-09-2011, the following fields can be got corrected through the concerned bank branch:
Assessment Year
Major Head Code
Minor Head Code
TAN/PAN
Total Amount
Nature of payment (TDS Codes)

The time window for the correction request by tax payer is as follows:

TAN/PAN => 7 days
Assessment Year => 7 days
Amount => 7 days
Other fields (Major head, Minor head, Nature of payment) => Within 3 months

The limit specified above is from the Challan deposited date. The time window for correction by the bank is 7 days from the date of receipt of correction request from the tax-payer.


Conditions:

The changes can be made by the banks, subject to following conditions:
Correction in Name is not permitted.
Any combination of correction of Minor Head and Assessment Year together is not allowed.
PAN/TAN correction will be allowed only when the name in the Challan matches with the name as per the new PAN/TAN.
The change of amount will be permitted only on the condition that the amount so corrected is not different from the amount actually received by the bank and credited to Govt. Account.
For a single challan, correction is allowed only once. However, where 1st correction request is made only for amount, a 2nd correction request will be allowed for correction in other fields.
There will be no partial acceptance of change correction request, i.e. either all the requested changes will be allowed, if they pass the validation, or no change will be allowed, if any one of the requested changes fails the validation test.

Procedure:

The tax-payer has to submit the request form for correction (in duplicate) to the concerned bank branch.
The tax-payer has to attach copy of original challan counterfoil.
In case of correction desired for challans in Form 280, 282, 283, the copy of PAN card is required to be attached.
In case of correction desired for payments made by a tax-payer (other than an individual), the original authorization with seal of the non-individual taxpayer is required to be attached with the request form.
A separate request form is to be submitted for each challan.



Procedure of challan correction by Assessing Officers (both physical and e-payment challans)

After the window period available to banks for challan correction, the assessee can make a request for correction to his or her assessing officer, who is authorized under the departmental OLTAS application to make such correction in challan data in bonafide cases, to enable credit of the taxes paid, to the concerned assessee.

Can I update a challan?
Yes. You can update a challan.

How can I update a challan?
You can update any of the details provided in the challan viz; CIN details, amounts etc.

Points to be kept in mind while updating challan:
identify the challan to be updated by
its sequence no as per regular statement
CIN, deposit amount as per regular statement
Update the challan detail as required.
Along with the updated values, the correction statement should contain value of the CIN and deposit amount as per regular statement as well.
Example: In order to correct challan serial number from 013 to 014 in the sixth challan of the regular statement filed by you, the steps as under need to be followed

1. Identify the challan by the sequence number as well as the CIN and deposit amount as per regular statement.
2. Update the value in the field challan serial number to 014.
3. Ensure that the value in the field Last Bank challan no is 013, i.e. as per regular statement.

Can I add a challan?
Yes. You can add a challan.

How can I add a challan?
You can add a new challan as well as the underlying deductee records. The procedure for adding a challan is as under:

1. Maintain the sequence of the new challan record in continuation to the sequence number of the last challan as per regular statement and add details of challan in this record.
2. Add the underlying deductee records and associate the same with the sequence number of the newly added challan.

Example: If a regular statement filed by you has six challans and you wish to add one more challan and underlying five deductees, the steps as under need to be followed:

1. Sequence of new challan being added should be 7.
2. Add underlying five deductees in the deductee annexure and associate them with new challan having sequence no. 7.

Can I delete a challan?
No. You cannot delete a challan.
Source: TIN-NSDL