When a trademark no longer identifies the origin and quality of goods or services then it is abandoned. This means that the owner’s rights regarding the trademark are forfeited and someone else may now use the trademark. This does not mean that you should start using a trademark that you think will be abandoned. Good-faith pre-abandonment use is only permissible to establish priority if there was no knowledge. Abandonment occurs either when a trademark is not being used and there is no intent to use or when the trademark becomes a generic term for the goods or services it is used for. In either case this now means it is not acting as an identifier of origin or quality. If a trademark has not been used for three consecutive years, then the owner must demonstrate their intent to resume commercial use or else the mark will be abandoned. Evidence that can be used to demonstrate intent to resume commercial use includes marketing proposals or targeted use only to specific customers. It is important remember the mantra use it or lose. Your rights hinge on your use.
This blog is not legal advice and is not specific to your application. You should always consult an attorney.