看了下ICA的网页,你的理解可能有点偏差。通常去警局或者ICA更新居住地址时,需要带上一份印有新住址的账单以证明你确实是住在那里,假如你没有类似的账单,那你就可以使用ICA“Online Pre-Notification of Change of Address (OPAD)”这个服务,之后ICA会寄一份信到你提供的地址做为你居住在那里的凭证,然后你带着这封信再去警局或者ICA完成更新
"Upon receipt of this letter which serves as the evidence of his new address, the IC holder can call at ICA, NPCs/NPPs to effect the change of address on this physical IC."