Updating fields using a button

[philwages]

I do auctions on eBay (all movie related items). So, I have a master database ('descriptions') that contains film descriptions. But sometimes I need different values (in a field called 'MrLister') than what I have permanently saved in my master database. So, I maintain my current listings in a separate table ('listings'). Sometimes I feel I want to permanently save the new value of 'MrLister', but sometimes I don't. So I figured I would just create a button on my form that automatically updated this value from 'listings' to 'descriptions' as an onclick event. I can't seem to find the right code for making this happen, so any help would be greatly appreciated.