Instructions how to change homecuttency

Take old currency out, put new currency in.

Honestly, do you really think a question so unspecific like this will get an awnser here? Why do you want to change the currency? Which version are we talking of? What have you tried already? And "currency" is written with r's, not with t's. The Baanboard community is always keen to help, but it's really no good style to throw in a one-liner like this for a problem like this, showing no care for your question whatsover, and expect someone to help you.

Anyway, if you really have to change the home currency, you will have to get a decent consultant to your site. If it can be done at all, it will cost you a fair amount of programming / money.