The provision of section 131(1A) states the summon for attendance and to produce books of accounts, statements of bank accounts, and details of all properties. Etc.
Power u/s 131(1A) is only an enabling power regarding discovery, production of evidence, etc, before entering into actual exercises of Search and seizure under S. 132
If the summon is mandated in person, then they have to appear in person and make submissions under oath. If the summon permits to get represented by an Authorised Representative, then AR may represent with proper Power of Attorney. Even if they are mandated to appear in person to make submissions under oath, AR may accompany and be present during the proceedings.
The authorized officer can record such a preliminary statement under section 131(1A) read with an Explanation to section 132(4)
The statement concluded, it is required to be mentioned i.e. who has examined the witnesses, who have cross-examined him, who was present, whether the statement is read over in the language known/understood by the witness, the statement should be true to his knowledge and belief, whether it is voluntary having been given without any threat or inducement, and whether it has been signed by the witness; his counsel, and by the AO.