Under the Negotiable Instruments Act, 1881, the court shall summon the person giving an affidavit if:

Section 145(2) says the court "may, if it thinks fit, and shall, on the application of the prosecution or the accused, summon and examine any person giving evidence on affidavit". The duty to summon is triggered by such an application; a bank's request or the witness's own consent does not create it.