These names seem familiar to me - I think we need to read through this old thread:
http://www.genealogistsforum.co.uk/f...hlight=calland
Also this one:
http://www.genealogistsforum.co.uk/f...hlight=calland
Callen / Calland would not be a case of changing their name, just people pronouncing / spelling it differently. A lot of people could not read and write in those days, so they would not be able to tell the clerks etc how to spell their name.