Yes. It is possible to add challan to filed e-TDS Return. For corrections in PAN masterpersonal informationdeductee details, and challan details, there is no need to request for Conso file (file correction statement). 

Payer/ Deductor can add new challan using the service ‘Request for Correction’ on TRACES provided the regular return is processed and DSC of a responsible person is registered with TRACES.   

If not then the payer/ deductor needs to file a correction statement (Revise Return) by downloading Conso File from TRACES.