Sure they can refuse any changes. And you can refuse any changes. But then you don't have a contract, and then you don't have an employement. So if they say "W

Sure they can refuse any changes. And you can refuse any changes. But then you don't have a contract, and then you don't have an employement. So if they say "We'll give you a job, under conditions X, Y, Z" and you say "I don't like Y", they could either say (a) "Well, OK, we'll offer you a job under conditions X and Z" (in which case you have a job), or (b) "Sorry Y is a deal breaker for us, no deal" in which case you don't have a job.