Why would you migrate to a different location unless you have a contract that state that you have the right to work from anywhere (or laying out the conditions, such as maximum time zone differences and such)?
Anything that is simply a current policy at a company basically has to be ignored. It's a nice to have but if you "can't live without that", go look for another job or adjust otherwise.
And even stuff that _is_ in your contract is not a full on guarantee either as contracts can be amended. Which you still have to sign but they will make it very hard for you not to sign those amendments. But at least it gives you some warning when that happens. I.e. you can refuse to sign and then you have time to look for another job while they figure out how to get you fired.
Anything that is simply a current policy at a company basically has to be ignored. It's a nice to have but if you "can't live without that", go look for another job or adjust otherwise.
And even stuff that _is_ in your contract is not a full on guarantee either as contracts can be amended. Which you still have to sign but they will make it very hard for you not to sign those amendments. But at least it gives you some warning when that happens. I.e. you can refuse to sign and then you have time to look for another job while they figure out how to get you fired.