Responsa for Bava Batra 61:8
אמר אמימר אנא נהרדעא אנא וסבירא לי דטוען וחוזר וטוען והלכתא טוען וחוזר וטוען:
[in the course of the case], or is he not allowed to alter his pleas? 'Ulla said: He is allowed to alter his pleas; the Nehardeans say, he is not allowed to alter his pleas. 'Ulla, however, admits that if this man had pleaded at first,' It belonged to my father and not to yours,' he could not later alter his plea [to say, 'It did belong to yours']. 'Ulla also admits that if a man does not amend his pleas in any way when in court, but after leaving the court comes In again and amends them, the rule that he may alter his original plea does not apply, because we assume that someone has suggested the amended plea to him. The Nehardeans [on their side] admit that if [after saying, 'It belonged to my father'] he pleads, 'my father who bought it from your father,' he is allowed to alter his plea [to this effect];<span class="x" onmousemove="('comment',' Because he is simply making his former plea more emphatic, and not altering it. ');"><sup>7</sup></span>
Teshuvot Maharam
A. It is customary for charity officers to advance their own money when the charity chest is empty and to collect it afterwards. Such officers' claims that money is due them from the chest are believed. Therefore, A is entitled to collect his two marks, and his subsequent explanation of his statement "I do not ask anything of you", should be accepted.
b) Q. Some members of the community are ready to testify in A's behalf. Is their testimony admissible as evidence?
A. The testimony of residents of a city is admitted as evidence in a case to which all the residents of the city are a party, if their testimony is against the interests of the city residents. Such testimony, however, is not admissible against the relatives of the witnesses.
SOURCES: Pr. 1012; Mordecai Hagadol, p. 301a; ibid. p. 350a; cf. Mord. B. B. 489; Weil, Responsa 124.