How soon can you change piercing jewelry?

I'm getting my lip pierced on Tuesday (my last day of work) but I'm starting a new job in less than 3 weeks. I don't know what their policy on piercings is yet, so I was wondering if it'd be safe to change to a retainer or less noticeable bar in this time? I want to know because I'd rather keep a job than keep a piercing haha
Oh and it's not my first piercing, I have 10 piercings already, 2 are oral so I know a bit about do's and dont's and I don't get infections easily, but I have never changed one so quickly before.
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Crown Jewel