Adding Table and Changing code

[CaiSupport]

We had someone help us write this code and now they are gone and the client wants changes. Currently we update the Access database (Customerservice) by matching with a Mas90 table. Everything was fine, but we were calculating the next date based on what was the last next date in access, they now want the next date calculated based on Invoice date. Original code query
UPDATE CustomerService INNER JOIN AR_95_UDF_ARInvoiceLines ON ([CustomerService].[Next Date]=[AR_95_UDF_ARInvoiceLines].[Nextservicedate]) AND (([CustomerService].[ID])=[AR_95_UDF_ARInvoiceLines].[Scheduleid]) SET CustomerService.[Previous Date] = [CustomerService].[Next Date], CustomerService.[Next Date] = UpdateServiceDates([CustomerService].[Next Date],[CustomerService].[Interval],[CustomerService].[Frequency]);
I need to match the AR_95_UDF_ARInvoiceLines.InvoiceNumber with ARN_InvHistoryHeader.InvoiceNumber so that the UpdateServicedates uses Invoice Date.