If you are with a family member or friend who is hearing impaired in a public place, it is always best to formulate a plan in how to locate one another, especially if you get separated.
Study a map of the place before you set off. Discuss an appropriate meeting place in case you get separated or if one gets lost. Both of you should rely on visual aids such as landmarks. If you are going to separate businesses, make sure you agree on a meeting time as well.
It is better for the hearing impaired to have a cellphone. Make sure that the cellphone is set on vibrate and that they have it in their person when they go out. You can also use text or e-mail features of the cellphone to send and receive messages.