Off topic:convert between vcf types

Question

[samuel.lipworth]

I currently a vcf file which describes in one file the variant call for all samples at all variable positions eg:

sample1, sample2, sample3, sample4, sample5
1  A  A  T  A  T
5  T  T  G  T  G

I want to convert to the vcf type which shows the call for a variable positions for one sample only eg:

sample1
1 A
5 T

I'm sure I used to know a programme which could do this - any ideas?