You can take the following action to correct the details in your Form 26AS:
1) In cases of a mistake made by the Deductor (e.g., your employer), you should contact the Deductor and request them to:
• File the TDS return if it is still pending
• Furnish a revised TDS return if they filed the return with incorrect details / wrong or no PAN
• If there is a mistake made by the bank (e.g., in tax amount, PAN), you should request the bank to rectify it in the challan details uploaded by the bank
Especially in cases of tax amount being wrong, it is mandated that you get it corrected – else you will not get a tax credit for deductions that are not mentioned in Form 26AS.