Goldfish help

[Ollivander84]

My last goldfish died today aged about 10, he was almost completely silver bless him! If I wanted to get another, do I do a full tank change? Or just part?
There's no fish in the tank now

Sorry to hear about your goldfish- a part of the family for so long!
Firstly.. How big is your tank?
I'm not sure what equipment you have running but if the water has been left "still" i.e. no movement at all, I would personally do a significant (preferably total) water change (unless of course you have a massive tank!)
If it was only recent and the water has continued to be circulated or filtered then a partial should be safe enough along with checking your parameters.