If you were in a relationship with a co-worker and decided to get married, how would you tell HR?

We work in the same dept. but not together. We've been dating privately for about 1 1/2 years. We would like to get married in the next few months, but we're unsure of how to handle it at work. It isn't prohibited. There are other married couples. We're afraid that one of us might get fired if we say something. How should we handle this?If you were in a relationship with a co-worker and decided to get married, how would you tell HR?
The best way is to ask for a transfer to different department for one of you. Usually, the company will make some sort of movement, as long you two not in a department, it should be okay. When one of you moved to a key position (someone who can promote or fire) ppl, then you have to leave the company. Talk to HR.If you were in a relationship with a co-worker and decided to get married, how would you tell HR?
Tell HR that you are in a relationship and that you felt that unless it was serious there was no reason to contact them and you wanted them to know in case of a promotion in which case your relationship would be prohibited.