{HEAD ~ The tieback member} of this invention is used in {TAIL ~ the contingency} that the tieback threads in the casing hanger become damaged 
is used in
{ HEAD ~ The tieback member } of this invention is used in { TAIL ~ the contingency } that the tieback threads in the casing hanger become damaged
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH