I'm halfway through my PhD and will be visiting another country for a conference. While I am there I would like to talk with some of the local researchers and hopefully visit their labs and discuss their research. I intend to email some of the researchers in my field in advance and ask if they would be happy to have a chat about their research and possibly visit their lab (briefly on the visit, more like a lab tour than anything else).
What is the best way to ask these PI's (via email) if I could meet with them while I am in town to visit their labs and discuss their research?