Amendment in non core field without using dsc (for pvt ltd)

Respected Sir

My query is related to Amendment in non care field 

situation is as follows 

1) currectly we are having 2 authorised signatory on gst portal. 1 signatory having DSC, 1 NO DSC

2) Signatory having DSC resigned on 30.04.2018 

3) now I want to add new authorised signatory having DSC 

but problem is HOW I CAN SUBMIT 'AMENDMENT IN NON CORE FIELD' APPLICATION WITHOUR DSC?

Please guide me 

thanking you