Ambiguity of "Lindsey told Jessica that she had cancer"

Lindsey told Jessica that she had cancer.

Who had cancer? Is there any rule in English to claim it definitely?

Solution 1:

This sentence is syntactically correct but semantically ambiguous. One may rewrite it as

Lindsey told Jessica that the former had cancer

to mean that Lindsey had cancer or

Lindsey told Jessica that the latter had cancer

to mean that Jessica had cancer.

Solution 2:

The best way to clarify the statement is to use direct speech instead of indirect speech.

"I have cancer" said Lindsey to Jessica

if Lindsey had cancer, or

"You have cancer" said Lindsey to Jessica

if Jessica had cancer.