I understand from your question you are asking if you can postpone the surveillance assessment by the accreditation body?
It depends on when your accreditation cycle ends and the certificate of accreditation expires. You need to refer to the specific policy of your accreditation body and engage with them. There may be some flexibility with the date for a surveillance assessment, however it depends on availability of assessors. If the laboratory is at the end of the accreditation cycle and the full reaccreditation assessment is due, the laboratory would need to close any nonconformances before the expiration date anyway.
Consider the laboratory’s commitment to clients, obligation as an accredited laboratory (contractual agreement with the accreditation body) and options. If there are major issues then they need to be identified, documented and addressed as a matter of priority. If these are minor issues that do not affect the validity of results, then acknowledge and start addressing them before the assessment. Then deal with the nonconformances raised by the accreditation body. If the validity of results are in question, then taking on work should typically be suspended until the issues are resolved. There are situations where a laboratory is obliged to go into voluntary accreditation suspension and cannot claim to be accredited until reassessed.