Planning the exit in advance

For example, lets say you bid a 1 lot and get filled, at a price 10, and the market
soon moves up, and you plan to exit at 15(arbitrary). Lets say I just got filled,
and price still at 10, if I offer a 1 lot at 15, and the price moves to 15, will
I exit my original long position, OR will I have 2 open positions, one long at 10 and
one short at 15?

Furthermore, is the above scenario(of what will happen) broker/platform dependent? If so, please state broker/platform.

I hope my question is clear.

Thanks

Had the same question once...
If you are trading exactly the same contract,
usually your second trade closes your position.
some companies, though, might "artificially", allow
you to have a buy and sell position open in exactly the
same product.

thanks for the reply, fantastic