InDesign RGB to CMYK Problems

I created an InDesign document (4 pages) that has various shapes that are different colors (yellow, green, etc.). The shapes are InDesign shapes (not imported graphics). We originally created the document to be exported as a PDF and shared online. The green shape color we used (a neon green) looks fine in RGB. However, when we try to export the document to CMYK (we decided that we need to be able to print the document on a CMYK printer also) the neon green color turns into a dark, forest green color. I'm pretty new to InDesign and I'm not sure how to replicate the neon RGB green to look the same in CMYK. Any help would be appreciated! Thanks.