microsoft access training - Full stops

In our databases we inherited there is a field for a client that starts with St. for saint. The full stop is causing problems but only for this client - every other client is unaffected. It would involve far too much work using current skills to manually change the hundreds of entries across the tables.

Is there a solution to this either by amending the word across all tables and all databases consistenty or by using slightly different code that doesn't fall down?

It falls down even when the full name is within speech marks. Which is frustrating.

Many thanks, Heather