Amending gst invoice of jan 2018 - possible?

Hi experts, 

In GSTR 1 return  of Jan 2018, I have made a mistake in filing the return, the amount in invoice is not correctly filed. (Invoice date is 17 Jan 2018, FY 17-18)

So B2B customer is saying they have not got ITC credit. 

Hence now I want to amend it. Can amended invoice be issued and uploaded now into March 2019 GST return? Will B2B customer then be able ITC credit? 

Kindly assist with the same

With regards

Vikas G