How to transfer cities?

Find a niche or area that is stronger in City B than City A and express interest for it as well as making a business case for you moving

In brokerage? Its not going to happen. Unless you're moving to open or lead an office CBRE wont allow you to "transfer cities."

If you can make a good case on being able to produce business in the new city I'm sure whoever the head of the office is would hire you on if you're a current producer. But you're basically going to have to interview in your new location.

Depends on how macro your line is. STNL dudes can work from Guam (I'd guess), but you're taking a HUGE step back if your working market dependent product and switch cities

Extremely complicated if you are in brokerage. Why would you leave your network in your market to go to a new market, and create a new network from scratch?

I see you have posted a good amount recently ranging from Minneapolis being a good CRE city to most profitable career path, to this post here. I don't know how old you are, but your page states you're an intern. So I think you need to sit down with yourself and determine what areas of CRE you are most interested in and apply to those relative positions. Then start worrying about if your market is profitable, or if you can transfer internally to a new location. Those answers will come later down the line.

If you're an intern, I'm not sure why you are worried about this as you have yet to start full time. Focus on your duties and hope you get a return offer.