Confused about pin

[Vakil Smallen]

I'm DMing a Starfinder game and the party is facing an incapacitator robot. I just need some clarification about the rules because a few things are confusing me.

In the first round, the robot managed to pin a player with a successful melee attack that was more than 13 above the player's KAC.
In the second round, does the robot need to roll again to maintain the pin? Or does the player roll to free themselves? If the robot as the attacker needs to roll, are they going for the same target number set by the player's KAC (as modified by being pinned)?
I think what's confusing me is Pathfinder's combat maneuver bonus vs defense rules which Starfinder doesn't seem to have.

Also, related by separate question. The robot only has one action per round as far as I can tell but the description seems to suggest it could fire it's pistol while grappling someone. Can someone confirm for me that it can't use its pistol in the same round that it is attempting to maintain a pin?

Thanks.

[HammerJack]

The grappled or pinned condition lasts until the end of your next turn, unless you renew it on your next turn with another grapple combat maneuver. If you attempt anether grapple maneuver, the target''s KAC is still modified by the grappled or pinned condition that they have.

Because grapple is a standard action, this robot could only attempt to grapple and fire a pistol in the same round if it had some special ability to do these things with nonstandard action economy.

[Vakil Smallen]

Thanks.