Yes, you can reclaim tax paid - depending on how much you earned, you may get it all back as you'll have an allowance/credit for the full year but will have only worked a few months. I presume you weren't on emergency tax and actually had a proper tax credit cert.
You can download form P50 from the revenue.ie site and send it back, along with P45 - see here:
[broken link removed]
If you get all your tax back, you won't get any more from the rental credit; if not, it's worth returning that form too. (I got that allowance for a couple of years without the owner's PPS number, just his name, etc.)
ATB,
A.