Does an assessment of the supplier’s existing, qualified device data demonstrate that the similar device you are considering will satisfy mission requirements?
This practice is known as qualification by similarity. If the new part being considered is, for example, manufactured at the same facility by the same staff, using the same materials, processes and test approaches as the qualified part, it is likely to be acceptable for your mission under a similar flight environment. That said, if the part qualified by similarity is a single-point failure, in a single-string application or in a mission-critical application, additional mitigations may be needed to further reduce risk.