Since you have a contract for 90 days, you
would have to get your agent's permission to be released from
the contract so you can go with the other agent.
Most of the time they will attempt to dissuade you from
making the change, but will release you because they don't
want to engender any bad will. The agent will be reluctant of
course, especially since you just "changed your mind," and
cannot point to any lack of performance problems with your
present agent.
The agent can refuse to release you from the listing
agreement and there are various reasons they may do so. In
that case, you're either stuck or you have to simply take your
home off the market for the rest of the listing period.
