Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Nic Walker Share on twitter by Sue Mitchell South African retailer Woolworths Holdings has turned to former Westpac chief executive Gail Kelly to help transform itself into a leading southern hemisphere retailer after last year's $2.1 billion acquisition of David Jones.

Answer: employer: Gail Kelly, Westpac