You can do it only after passing Diploma. You should send a form regarding this to IEI, Kolkata.
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A Technician member, after acquiring diploma level qualification, changes
his membership to Senior Technician, s/he shall be considered, on request,
as exempted from Section 'A' Examination, provided s/he has secured
exemption (obtained Grade 'C' or above with minimum GPA being 6) in four
common subjects of same nomenclature in both Section 'A' (Non-diploma) and
Section 'A' (Diploma) of revised syllabi.
No pass grade card of Section 'A' shall be issued. S/he shall be eligible to
register for Section 'B', with requisite fee, with an undertaking that s/he
shall not claim pass grade card for Section 'A'. The CGPA shall be
calculated only on the basis of Section 'B' Examination, project work and
laboratory experiments.
In case the Technician Member secured exemption in one or more common
subject(s) of same nomenclature in both the schemes of revised syllabi,
grade in common subject(s) can be carried forward, on request, after change
of her/his membership.
Important Note
You will not get Section A marks sheet. In the certificate - "Section A was exempted" will be mentioned. This may trouble while applying for job!

