Hello guys

I'm getting a datetime from a .js file. This datetime have a random time, and I want to modify it
to be 14:00:00 at first time. I have to be able to modify this time later. I'm doing it with an @api.onchange, but then I can't modify the hour. It always return to 14:00:00. 

The best way to do it I think is to execute @api.onchange only once, is it a way to do this? I've tried depends and model to, but doesn't work.

Here es my code

@api.onchange('checkin')
def _get_checkin(self):
    if self.checkin:
        self.checkin = self.checkin.strftime("%Y-%m-%d 14:00:00")

checkin = fields.Datetime(
    "Expected-Date-Arrival",
    required=True,
    readonly=True,
    states={"draft": [("readonly", False)]},
    store=True,
)